Chapter 2. Punctuation, Mechanics, Capitalization, and Spelling

 Habits in writing as in life are only useful if they are
broken as soon as they cease to be advantageous.
—W. Somerset Maugham

This chapter is about habit. As Samuel Beckett once noted, “Habit is the ballast that chains the dog to his vomit.” It is amazing how consistently we repeat the exact same little errors out of mere habit. However, we can tackle these habits by identifying them as patterns and writing with an eye for them. As a graduate student, I once misspelled the word “separate” (using an “e” in the middle) 16 times on an exam. My professor circled the offending letter each time and glibly noted, “I wish you could spell better.” His chiding cured me, and (knock wood) I have not misspelled “separate” since. Many students find that they have picked up the habit of putting commas in automatically before prepositions or even after conjunctions rather than before. Once such habits are identified, however, they can be addressed effectively.

No matter how niggling they may seem, details about punctuation, mechanics, capitalization, and spelling are important to master. Even with the spell checker and grammar checker eternally activated, we can make plenty of tiny mistakes that deeply affect sentence meaning. I know of an engineer who has repeatedly reported inaccurate dollar amounts to clients because of his sloppy proofreading. I have read government reports by well-published scientists where the colon was misused more than a dozen times in a single report. Even capitalization rules can be highly important to meaning: a student in geology, for example, must be aware of whether or not to capitalize “ice age” (yes when you mean the specific glacial epoch; no when you mean any of a series of cold periods alternating with periods of relative warmth). Finally, small mechanical errors (such as abbreviating a term or acronym improperly) reflect a general sloppiness and disregard for convention.

So work on the little things. Seek to understand punctuation marks as units affecting grammar and meaning, and accept proper spelling, capitalization, and mechanics as professional necessities. This chapter will help you to do so without immersing you into a grammatical swamp.

Self-Study

For further lessons on punctuation, visit these pages:

"A Brief History of Punctuation" article from about.com

"Brief Overview of Punctuation" article from Purdue's Online Writing Lab (OWL)

Hyphens

A wise writer once said, “If you take hyphens seriously you will surely go mad.” Hyphens belong to that category of punctuation marks that will hurt your brain if you think about them too hard, and, like commas, people disagree about their use in certain situations. Nevertheless, if you learn to use hyphens properly, they help you to write efficiently and concretely, and you will have to use them regularly because of the nature of technical writing. Because concepts in science and engineering frequently rely on word blends and complex word relationships, the best writers in these fields master the use of the hyphen.

The Hyphen's Function

Fundamentally, the hyphen is a joiner. It joins:

  • two nouns to make one complete word (kilogram-meter);
  • an adjective and a noun to make a compound word (accident-prone);
  • two words that, when linked, describe a noun (agreed-upon sum, two-dimensional object);
  • a prefix with a noun (un-American);
  • double numbers (twenty-four);
  • numbers and units describing a noun (1000-foot face; a 10-meter difference)
  • “self” and “well” words (self-employed, well-known);
  • ethnic labels (Irish-American);
  • new word blends (cancer-causing, cost-effective);
  • prefixes and suffixes to words, in particular when the writer wants to avoid doubling a vowel or tripling a consonant (anti-inflammatory; shell-like).

The rule of thumb I apply when using the hyphen is that the resulting word must act as one unit; therefore, the hyphen creates a new word—either a noun or a modifier—that has a single meaning. Usually, you can tell whether a hyphen is necessary by applying common sense and mentally excluding one of the words in question, testing how the words would work together without the hyphen. For example, the phrases “high-pressure system,” “water-repellent surface,” and “fuel-efficient car” would not make sense without hyphens, because you would not refer to a “high system,” a “water surface,” or a “fuel car.” As your ears and eyes become attuned to proper hyphenation practices, you will recognize that both meaning and convention dictate where hyphens fit best.

Self-Study

The following websites offer exercises on using the hyphen properly, as well as the correct answers to the exercise questions:

Hyphenation exercises from the Little, Brown Handbook

Hyphen practice from the Chicago-Kent College of Law

Examples of Properly Used Hyphens

Some examples of properly used hyphens follow. Note how the hyphenated word acts as a single unit carrying a meaning that the words being joined would not have individually.

small-scale study
two-prong plug
strength-to-weight ratio
high-velocity flow
well-known example
frost-free lawn
self-employed worker
one-third majority
coarse-grained wood
decision-making process
blue-green algae
air-ice interface
silver-stained cells
protein-calorie malnutrition
membrane-bound vesicles
phase-contrast microscope
long-term-payment loan
cost-effective program
time-dependant variable
radiation-sensitive sample
long-chain fatty acid

When Hyphens Are Not Needed

By convention, hyphens are not used in words ending in -ly, nor when the words are so commonly used in combination that no ambiguity results. In these examples, no hyphens are needed:

finely tuned engine blood pressure sea level
real estate census taker atomic energy
civil rights law public utility plant carbon dioxide

Prefixes and Suffixes

Most prefixes do not need to be hyphenated; they are simply added in front of a noun, with no spaces and no joining punctuation necessary. The following is a list of common prefixes that do not require hyphenation when added to a noun:

after anti bi bio co
cyber di down hetero homo
infra inter macro micro mini
nano photo poly stereo thermo

Common suffixes also do not require hyphenation, assuming no ambiguities of spelling or pronunciation arise. Typically, you do not need to hyphenate words ending in the following suffixes:

able less fold like wise

Commonly Used Word Blends

Also, especially in technical fields, some words commonly used in succession become joined into one. The resulting word’s meaning is readily understood by technical readers, and no hyphen is necessary. Here are some examples of such word blends, typically written as single words:

blackbody groundwater airship
downdraft longwall upload
setup runoff blowout

Apostrophes

As you already know, apostrophes are used to form both contractions—two words collapsed into one—and possessives. Handily, we can virtually ignore the issue of contractions here, since they are so easily understood and are rarely used in technical writing. With possessives, the apostrophe is used, typically in combination with an “s,” to represent that a word literally or conceptually “possesses” what follows it.

a student’s paper              the county’s borders
a nation’s decision            one hour’s passing

Apostrophes with Words ending in “s”

Although practices vary, for words that already end in “s,” whether they are singular or plural, we typically indicate possession simply by adding the apostrophe without an additional “s.”

Illinois’ law                    Student Affairs’ office
Mars’ atmosphere        interviewees’ answers

Apostrophes with Acronyms and Numbers

In technical writing, acronyms and numbers are frequently pluralized with the addition of an “s,” but there is typically no need to put an apostrophe in front of the “s.” Therefore, “SSTs” (sea surface temperatures) is more acceptable than “SST’s” when your intention is simply to pluralize. Ideally, use the apostrophe before the “s” with an acronym or a number only to show possession (i.e., “an 1860’s law”; “DEP’s testing”) or when confusion would otherwise result (“mind your p’s and q’s”).

Possessives without the Apostrophe

Convention, frequency of usage, and—to be honest—the economy of advertising, sometimes dictate that the apostrophe is dropped. In proper names that end in “s,” especially of geographic locations and organizations, the apostrophe is often omitted. And in everyday combinations where possession is automatically understood, the apostrophe is often dropped.

United States government               Hells Canyon
Veterans Highway                            Harpers Ferry
mens room                                       Johns Hopkins University

Self-Study

For the confused and curious, here are some “Apostrophes for Dummies” websites:

"Guidelines for Using Apostrophes Correctly" page from about.com

"Using Apostrophes to Show Possession" page from dummies.com

Quotation Marks

Despite what you may see practiced—especially in advertising, on television, and even in business letters—the fact is that the period and comma go inside the quotation marks all of the time. Confusion arises because the British system is different, and the American system may automatically look wrong to you, but it is simply one of the frequently broken rules of written English in America: The period and comma go inside the quotation marks.

Correct: The people of the pine barrens are often called “pineys.”

Incorrect: The people of the pine barrens are often called “pineys”.

However, the semicolon, colon, dash, question mark, and exclamation point fall outside of the quotation marks (unless, of course, the quoted material has internal punctuation of its own).

This measurement is commonly known as “dip angle”; dip angle is the angle formed between a normal plane and a vertical.

Built only 50 years ago, Shakhtinsk—“minetown”—is already seedy.

When she was asked the question “Are rainbows possible in winter?” she answered by examining whether raindrops freeze at temperatures below 0 °C. (Quoted material has its own punctuation.)

Self-Study

More advice on quotation marks, including conventions for using them with direct and indirect quotations, is available online at:

Advice on using quotation marks from Purdue's Online Writing Lab (OWL)

Advice on using quotation marks from St. Cloud State University

Semicolons, Colons, and Dashes

Punctuation marks: terribly powerful in the right hands. Punctuation marks are silent allies, and you can train yourself to exploit them as such. Punctuation marks do not just indicate sound patterns—they are symbols that clarify grammatical structure and sentence meaning. And, as I demonstrate in the writing of this paragraph, punctuation marks showcase your facility with the language. What follows are some basics about three of the most powerful and most commonly misused punctuation marks.

The Semicolon

The semicolon is often misused in technical writing; in fact, it is often confused with the colon. Grammatically, the semicolon almost always functions as an equal sign; it says that the two parts being joined are relatively equal in their length and have the same grammatical structure. Also, the semicolon helps you to link two things whose interdependancy you wish to establish. The sentence parts on either side of the semicolon tend to “depend on each other” for complete meaning. Use the semicolon when you wish to create or emphasize a generally equal or even interdependent relationship between two things. Note the interdependent relationship of the two sentence parts linked by the semicolon in this example:

The sonde presently used is located in the center of the borehole; this location enables the engineer to reduce microphonics and standoff sensitivity.

Here, we see how the second half of the sentence helps to explain a key detail (the sonde location) of the first half. The semicolon, along with the repetition of the word “location,” helps to draw our attention to the explanation.

The semicolon is also handy for linking a series of parallel items that could otherwise be confused with each other. One savvy student used the semicolon in a job description on her resume as follows:

As an engineering assistant, I had a variety of duties: participating in pressure ventilation surveys; drafting, surveying, and data compilation; acting as a company representative during a roof-bolt pull test.

The Colon

The colon: well-loved but, oh, so misunderstood. The colon is not just used to introduce a list; it is far more flexible. The colon can be used after the first word of a sentence or just before the final word of a sentence. The colon can also be used to introduce a grammatically independent sentence. Thus, I call it the most powerful of punctuation marks.

The colon is like a sign on the highway, announcing that something important is coming. It acts as an arrow pointing forward, telling you to read on for important information. A common analogy used to explain the colon is that it acts like a flare in the road, signaling that something meaningful lies ahead.

Use the colon when you wish to provide pithy emphasis.

To address this problem, we must turn to one of the biologist’s most fundamental tools: the Petri dish.

Use the colon to introduce material that explains, amplifies, or summaries what has preceded it.

The Petri dish: one of the biologist’s most fundamental tools.

In low carbon steels, banding tends to affect two properties in particular: tensile ductility and yield strength.

The colon is also commonly used to present a list or series, which comes in handy when there is a lot of similar material to join:

A compost facility may not be located as follows: within 300 feet of an exceptional-value wetland; within 100 feet of a perennial stream; within 50 feet of a property line.

The Dash

The dash—which is typically typed as two hyphens or as one long bar (available on your word processor’s “symbol” map)—functions almost as a colon does in that it adds to the preceding material, but with extra emphasis. Like a caesura (a timely pause) in music, a dash indicates a strong pause, then gives emphasis to material following the pause. In effect, a dash allows you to redefine what was just written, making it more explicit. You can also use a dash as it is used in the first sentence of this paragraph: to frame an interruptive or parenthetical-type comment that you do not want to de-emphasize.

Jill Emery confirms that Muslim populations have typically been ruled by non-Muslims—specifically Americans, Russians, Israelis, and the French.

The dissolution took 20 minutes—much longer than anticipated—but measurements were begun as soon as the process was completed.

Finally, the dash we typically use is technically called the “em dash,” and it is significantly longer than the hyphen. There is also an “en dash”—whose length is between that of the hyphen and the em dash, and its best usage is to indicate inclusive dates and numbers:

July 6–September 17            pp. 48–56.

Like the em dash, the en dash is typically available on your word processor’s symbol map, or it may even be inserted automatically by your word processor when you type inclusive numbers or dates with a hyphen between them. When you type the hyphen, en dash, and em dash, no spaces should appear on either side of the punctuation mark.

Self-Study

For more good-natured advice on using semicolons, colons, and dashes, visit these two fun sites:

"Semicolons, Colons, and Dashes" webpage from about.com

Writing tips from the "Punctuation Junction"

Commas

These little demons compound and trivialize the nightmares of many a professor after an evening of reading student papers. A sure way to irritate educated readers of your work is to give them an overabundance of opportunities to address your comma problems. It is easy but dangerous to take the attitude that Sally once did in a Peanuts comic strip, asking Charlie Brown to correct her essay by showing her “where to sprinkle in the little curvy marks.”

You have probably heard the common tips on using commas: “Use one wherever you would naturally use a pause,” or “Read your work aloud, and whenever you feel yourself pausing, put in a comma.” These techniques help to a degree, but our ears tend to trick us and we need other avenues of attack. However, it seems impossible to remember or apply the 17 or so grammatical explanations of comma usage that you were probably introduced to way back in 8th grade. (For example: “Use commas to set off independent clauses joined by the common coordinating conjunctions. . . . Put a comma before the coordinating conjunction in a series.”) Perhaps the best and most instructive way, then, for us to approach the comma is to remember its fundamental function: it is a separator. Knowing this, it is useful to determine what sorts of things generally require separation. In sum, commas are used to separate complete ideas, descriptive phrases, and adjacent items, and before and after most transition words.

Comma Rules

Complete ideas need to be separated by a comma because, by definition, they could be grammatically autonomous, but the writer is choosing to link them. Complete ideas are potentially whole sentences that the writer chooses to link with a conjunction such as “and” or “but.”

Digital recordings made it possible to measure the nuclear magnetic signal at any depth, and this allowed for a precise reading to be taken at every six inches.

Note how the second half of this sentence contains both a subject (“this”) and a verb (“allowed”), indicating that a second complete idea is presented, and thus a comma is required.

Descriptive phrases often need to be separated from the things that they describe in order to clarify that the descriptive phrases are subordinate (i.e., they relate to the sentence context, but are less responsible for creating meaning than the sentence’s subject and verb). Descriptive phrases tend to come at the very beginning of a sentence, right after the subject of a sentence, or at the very end of a sentence.

Near the end of the eighteenth century, James Hutton introduced a point of view that radically changed scientists’ thinking about geologic processes.

James Lovelock, who first measured CFCs globally, said in 1973 that CFCs constituted no conceivable hazard.

All of the major industrialized nations approved, making the possibility a reality.

In each of these cases, note how the material separated by the comma (e.g., “making the possibility a reality”) is subordinate—i.e., it carries context in the sentence, but the primary sentence meaning is still derived from the subject and verb. In each example, the phrase separated by the comma could be deleted from the sentence without destroying the sentence’s basic meaning.

Adjacent items are words or phrases that have some sort of parallel relationship, yet are different from each other in meaning. Adjacent items are separated so that the reader can consider each item individually.

Weathering may extend only a few centimeters beyond the zone in fresh granite, metamorphic rocks, sandstone, shale, and other rocks.

The river caught fire on July 4, 1968, in Cleveland, Ohio.

This approach increases homogeneity, reduces the heating time, and creates a more uniform microstructure.

In the first sentence, the commas are important because each item presented is distinctly different from its adjacent item. In the second example, the dates (July 4, 1968) and places (Cleveland, Ohio) are juxtaposed, and commas are needed because the juxtaposed items are clearly different from each other. In the third example, the three phrases, all beginning with different verbs, are parallel, and the commas work with the verbs to demonstrate that “This approach” has three distinctly different impacts.

Finally, transition words add new viewpoints to your material; commas before and after transition words help to separate them from the sentence ideas they are describing. Transition words tend to appear at the beginning of or in the middle of a sentence, and, by definition, the transition word creates context that links to the preceding sentence. Typical transition words that require commas before and after them include however, thus, therefore, also, and nevertheless.

Therefore, the natural gas industry can only be understood fully through an analysis of these recent political changes.

The lead precursor was prepared, however, by reacting pure lead acetate with sodium isopropoxide.

Self-Study

There are plenty of websites devoted to exercises on comma usage for those who wish to self-study.  Here are two I recommend:

Comma quiz from myenglishlessons.net

A 10-question comma quiz from the Pearson Longman Lab Manual Online

Using a Comma Before “And”

It is true that commas are sometimes optional, depending on sentence meaning and the writer’s taste, and many writers choose not to put a comma before the “and” in a series (also known as the “serial comma”) involving a parallel list of words. For example, some would write the sentence “I am industrious, resourceful and loyal,” using no comma before the “and.” This practice is fine as long as you are consistent in applying it. However, I, and the grammar handbooks I consult, recommend a comma even in these circumstances, because—even in the example provided—there is a slight pitch and meaning change between the terms “resourceful” and “loyal.”

Most importantly, if the “and” is part of a series of three or more phrases (groups of words) as opposed to single words, you should use a comma before the “and” to keep the reader from confusing the phrases with each other.

Medical histories taken about each subject included smoking history, frequency of exercise, current height and weight, and recent weight gain.

By always using a comma before the “and” in any series of three or more, you honor the distinctions between each of the separated items, and you avoid any potential reader confusion. The bottom line is this: When you use a comma before the “and” in a series of three or more items or phrases, you are always correct.

That noted, be aware that some professors and many journals will not favor the use of the comma before an “and” in a series (for the journals, it is literally cheaper to print fewer commas).

Self-Study

Plenty of online debate is devoted to the serial comma issue. Here are some related thoughts from "Punctuation Man" and the “Grammar Girl”:

Punctuation Man endorsing the serial comma

Grammar Girl weighing in on the serial comma

Comma Overuse

Perhaps the best way to troubleshoot your particular comma problems, especially if they are serious, is to identify and understand the patterns of your errors. We tend to make the same mistakes over and over again; in fact, many writers develop the unfortunate habit of automatically putting commas into slots such as these:

  • between the subject and verb of a sentence
  • after any number
  • before any preposition
  • before or after any conjunction

Thus, incorrect sentences such as these appear in papers:

The bushings, must be adjusted weekly, to ensure that the motor is not damaged.

Many botanists still do not fully appreciate these findings even after 22 years, following the publication of the discovery paper.

Other manufactured chemicals that also contain bromine are superior for extinguishing fires in situations where people, and electronics are likely to be present.

The price of platinum will rise, or fall depending on several distinct factors.

If the commas above look fine to you, then you may be in the habit of using commas incorrectly, and you will need to attack your specific habits, perhaps even in a routine, repetitive fashion, in order to break yourself of them. Similarly, it is common for someone to have to look up the same tricky word dozens of times before committing its proper spelling to memory. As with spelling, commas (or the absence of commas) must be repeatedly challenged in your writing. As you perfect your comma usage you are also recognizing and reevaluating your sentence patterns, and the rewards are numerous. There is no foolproof or easy way to exorcise all of your comma demons, but reminding yourself of the comma’s basic function as a separator and justifying the separation of elements whenever you use the comma is a good beginning. I often recommend to students with comma problems that they re-read their work one last time, just focusing on their comma use, before turning in a paper as a final version. In the end, you simply must make a habit of reading, writing, and revising with comma correctness in mind, and remember that commas have much to do with sentence wording, which is always in the control of the writer.

To demonstrate this last point, Lewis Thomas, a clever essayist as well as a physician and poet, shows us how to use commas effectively—as well as how to word a long sentence so that commas are not overused—in this excerpt from “Notes on Punctuation”:

The commas are the most useful and usable of all the stops. It is highly important to put them in place as you go along. If you try to come back after doing a paragraph and stick them in the various spots that tempt you you will discover that they tend to swarm like minnows into all sorts of crevices whose existence you hadn’t realized and before you know it the whole long sentence becomes immobilized and lashed up squirming in commas. Better to use them sparingly, and with affection, precisely when the need for one arises, nicely, by itself. 

The Period

Though a seemingly trivial punctuation mark, the period does present some knotty challenges, especially in technical writing. We all know to place a period to signal the termination of a simple sentence that makes a statement. However, here are a few more specialized rules:

  • Do not use a period in combination with other punctuation marks unnecessarily, especially when a quotation is involved. In such an instance, end the sentence naturally on whatever punctuation mark is logical (e.g., a question mark).
  • Avoid using periods at the ends of abbreviated units of measure, except when the period might be confused with another word. (Therefore, so that it’s not confused with the word “in,” use “in.” to abbreviate “inches.”)
  • When using a period in conjunction with parentheses, the period comes after the parentheses are closed if the parenthetical comment itself is part of the larger sentence (as in the first bulleted sentence above, and this one). The period comes inside the parentheses only when the parentheses themselves contain a complete independent sentence. (See the example in the second bulleted sentence above, as well as this sentence.)
  • By convention, if an abbreviated word (such as “etc.”) ends a sentence, let a single period signal the sentence’s end—two periods in a row would be incorrect.
  • In acronyms commonly understood or commonly used in your field (ASTM, EPA, US, GIS), do not use periods after the capital letters.
  • Do use periods after abbreviations and acronyms that are forms of address, initials within proper names, earned degrees, and when expressing measures of time (Dr. Bauer; M.S. degree; Steven S. Wilson, Jr.; 5:00 p.m.; 10 B.C.).

Self-Study

For everything you always wanted to know about the period, but neglected to ask, visit these sites:

Punctuation rules from infoplease.com

"English 101: Punctuation: Periods" website from thinkouthere.com

 

Parentheses

We are used to using parentheses to identify material that acts as an aside (such as this brief comment) or to add incidental information, but in technical writing the rules for using parentheses can be more nuanced.  Some more specialized functions of parentheses include:

  • To introduce tables or figures within a sentence:
In pulse-jet collectors (Figure 3), bags are supported from a metal cage fastened onto a cell plate at the top of the collector. 
  • To represent converted units:
The funnel used for this experiment was 7 in. (17.8 cm) in length.
  • When enumerating:
The system has three principal components: (1) a cleaning booth, (2) an air reservoir, and (3) an air spray manifold.
  • To indicate product manufacturer names:
The filtering process involves a 10-mm Dorr-Oliver cyclone (Zefon International).
  • To introduce an acronym after it has been written out:
Units will be expressed in cubic feet per minute (cfm).

Finally, it should be noted that punctuation used alongside parentheses needs to take into account their context. If the parentheses enclose a full sentence beginning with a capital letter, then the end punctuation for the sentence falls inside the parentheses. For example:

Typically, suppliers specify air to cloth ratios of 6:1 or higher. (However, ratios of 4:1 should be used for applications involving silica or feldspathic minerals.)

If the parentheses indicate a citation at the end of a sentence, then the sentence’s end punctuation comes after the parentheses are closed:

In a study comparing three different building types, respirable dust concentrations were significantly lower in the open-structure building (Hugh et al., 2005).

Finally, if the parentheses appear in the midst of a sentence (as in this example), then any necessary punctuation (such as the comma that appeared just a few words ago) is delayed until the parentheses are closed.

Abbreviations and Acronyms

Abbreviations (the shortened form of a word or phrase) and acronyms (words formed from the initial letters of a phrase) are commonly used in technical writing. In some fields, including chemistry, medicine, computer science, and geographic information systems, acronyms are used so frequently that the reader can feel lost in an alphabet soup. However, the proper use of these devices enhances the reading process, fostering fluid readability and efficient comprehension.

Some style manuals devote entire chapters to the subject of abbreviations and acronyms, and your college library no doubt contains volumes that you can consult when needed. Here, I provide just a few principles you can apply in using abbreviations and acronyms, and in the next section I offer a table of some of the forms most commonly used by student writers.

Abbreviations

  • Typically, abbreviate social titles (Ms., Mr.) and professional titles (Dr., Rev.).
  • In resumes and cover letters, avoid abbreviations representing titles of degrees (e.g., write out rather than abbreviate “Bachelor of Science”).
  • Follow most abbreviations with a period, except those representing units of measure (“Mar.” for March; “mm” for millimeter). See the table that follows for further guidance.
  • Typically, do not abbreviate geographic names and countries in text (i.e., write “Saint Cloud” rather than “St. Cloud”; write “United States” rather than “U.S.”). However, these names are usually abbreviated when presented in “tight text” where space can be at a premium, as in tables and figures.
  • Use the ampersand symbol (&) in company names if the companies themselves do so in their literature, but avoid using the symbol as a narrative substitute for the word “and” in your text.
  • In text, spell out addresses (Third Avenue; the Chrysler Building) but abbreviate city addresses that are part of street names (Central Street SW).
  • Try to avoid opening a sentence with an abbreviation; instead, write the word out.
  • When presenting a references page, follow the conventions of abbreviation employed by a journal in your field. To preserve space, many journals commonly use abbreviations, without periods, in their references pages (e.g., “J” for Journal; “Am” for “American”).

Acronyms

  • Always write out the first in-text reference to an acronym, followed by the acronym itself written in capital letters and enclosed by parentheses. Subsequent references to the acronym can be made just by the capital letters alone. For example:

                       Geographic Information Systems (GIS) is a rapidly expanding field. GIS technology . . .

  • Unless they appear at the end of a sentence, do not follow acronyms with a period.
  • Generally, acronyms can be pluralized with the addition of a lowercase “s” (“three URLs”); acronyms can be made possessive with an apostrophe followed by a lowercase “s” (“the DOD’s mandate”).
  • As subjects, acronyms should be treated as singulars, even when they stand for plurals; therefore, they require a singular verb (“NIOSH is committed to . . .”).
  • Be sure to learn and correctly use acronyms associated with professional organizations or certifications within your field (e.g., ASME for American Society of Mechanical Engineers; PE for Professional Engineer).
  • With few exceptions, present acronyms in full capital letters (FORTRAN; NIOSH). Some acronyms, such as “scuba” and “radar,” are so commonly used that they are not capitalized. Consult the table that follows in the next section to help determine which commonly used acronyms do not appear in all capital letters.
  • When an acronym must be preceded by “a” or “an” in a sentence, discern which word to use based on sound rather than the acronym’s meaning. If a soft vowel sound opens the acronym, use “an,” even if the acronym stands for words that open with a hard sound (i.e., “a special boat unit,” but “an SBU”). If the acronym opens with a hard sound, use “a” (“a KC-135 tanker”).

Click here to download a pdf of a table of commonly used abbreviations and acronyms.

Click here to open a table of commonly used abbreviations and acronyms.

Table of Commonly used Abbreviations and Acronyms

Use this table to check the proper spelling, capitalization, and punctuation of commonly used abbreviations and acronyms. For a much more detailed listing of abbreviations and acronyms, you can check in the back pages of many dictionaries, or consult the Chicago Manual of Style (also available online to subscribers) or the free online version of the United States Government Printing Office Style Manual.

A or amp ampere
a.m. ante meridiem, before noon
Assembler Assembler computer language
atm standard atmosphere
Ave. avenue
B.A. Bachelor of Arts
BASIC BASIC computer language
Blvd. boulevard
BP boiling point
B.S. Bachelor of Science
Btu British thermal unit
oC degrees Celsius
cd  candela
CDC  Centers for Disease Control
CFR  Code of Federal Regulations
CIA  Central Intelligence Agency
cm  centimeter
COBOL  COBOL computer language
Corp.  corporation
D  darcy
DEP Department of Environmental Protection
DOD Department of Defense
DOT Department of Transportation
engg. engineering
engr. engineer
e.g. exempli gratia, for example
EPA Environmental Protection Agency
et al.  et alii, and others
etc. et cetera, and so forth
oF degrees Fahrenheit
FBI Federal Bureau of Investigation
FCC Federal Communications Commission
FDA Food and Drug Administration
fig. figure
FORTRAN FORTRAN computer language
ft foot
gal. gallon
ha hectare
h hour
HP horsepower
HTML hypertext markup language
Hz hertz
i.e. id est, that is
in inch
Inc. incorporated
K Kelvin
kg kilogram
kw kilowatt
kWh          kilowatt-hour
l or L liter
LAFTA Latin American Free Trade Association
lb pound
m meter
mHz megahertz
min. minute
mol mole
M.S. Master of Science
NASA National Aeronautics and Space Administration
neg negative
NIH National Institutes of Health
NIOSH National Institute for Occupational Safety and Health
 NM  nautical mile
 NOAA  National Oceanic and Atmospheric Administration
 NSF  National Science Foundation
 OPEC  Organization of Petroleum Exporting Countries
 OSHA Occupational Safety and Health Administration
p. page
Pascal  Pascal computer language
 Ph.D.  Philosophiae Doctor, Doctor of Philosophy
 p.m.  post meridiem, after noon
 pos  positive
 pp. pages
pt. pint
qt. quart
radar  radio detecting and ranging
 RPM  revolutions per minute
 scuba  self-contained underwater breathing apparatus
 sec. or s  second
 sq  square
 STP  standard temperature and pressure
 temp  temperature
 Univ.  university
 URL  uniform resource locator
 USGS  United States Geological Survey
 vol.  volume

Self-Study

For comprehensive online acronyms dictionaries, especially for technical fields such as chemistry and medicine, I recommend these sites:

Online acronyms dictionary

Searchable acronyms database, sorted by discipline

Expressing Temperatures and Numbers

Style manuals, professional societies, and journals specific to your field publish thorough guidelines about how to handle small matters of mechanics. For instance, Suggestions to Authors of the Reports of the United States Geological Survey addresses such issues as whether to use the chemical name or symbol in writing; the American Meteorological Society’s Authors’ Guide dictates how one should express time, time zone, day, month, and year in writing. Chase down such sources within your field for specifics on matters of mechanics.

Two especially noteworthy issues of mechanics that arise regularly in technical writing are how to handle temperature measurements and numbers. Some guidelines on these matters follow.

Referring to Temperature Measurements

Degree measures of temperature are normally expressed with the ° symbol rather than by the written word, with a space after the number but not between the symbol and the temperature scale:

The sample was heated to 80 °C.

Unlike the abbreviations for Fahrenheit and Celsius, the abbreviation for Kelvin (which refers to an absolute scale of temperature) is not preceded by the degree symbol (i.e., 12 K is correct).

Writing about Numbers

The rules for expressing numbers in technical writing are relatively simple and straightforward:

All important measured quantities—particularly those involving decimal points, dimensions, degrees, distances, weights, measures, and sums of money—should be expressed in numeral form (e.g., 1.3 seconds, $25,000, 2 amperes).
Unless they appear as part of a string of larger related numbers, counted numbers of ten or below should be written out.
If possible, a sentence should not begin with a number, but if it does the number should be written out.
Treat similar numbers in grammatically connected groups alike.

Following these rules, here are some examples of properly expressed numbers:

The depth to the water at the time of testing was 16.16 feet.

For this treatment, the steel was heated 18 different times.

Two dramatic changes followed: four samples exploded and thirteen lab technicians resigned.

Self-Study

Check out these handy resources related to expressing numbers and numerals in text:

Technical writing tips for using numbers from a company president offering online technical writing courses

"Using Numbers, Writing Lists" advice from Capital Community College website

Capitalization

As a technical writer, who must often refer to such things as geographic locations, company names, temperature scales, and processes or apparatuses named after people, you must learn to capitalize consistently and accurately. What follows are ten fundamental rules for capitalization. Check out the first rule. It gets fumbled in papers all the time.

Capitalize the names of major portions of your paper and all references to figures and tables. Note: Some journals and publications do not follow this rule, but most do.

my Introduction Airshaft 3
see Figure 4 Table 1
Appendix A Graph

Capitalize the names of established regions, localities, and political divisions.

Wheeling Township the French Republic
Lancaster County the United Kingdom
the Wheat Belt the Arctic Circle

Capitalize the names of highways, routes, bridges, buildings, monuments, parks, ships, automobiles, hotels, forts, dams, railroads, and major coal and mineral deposits.

Highway 13 Route 1
Michigan Avenue the White House
Alton Railroad the Statue of Liberty
Herrin No. 6 seam the Queen Elizabeth

Capitalize the proper names of persons, places and their derivatives, and geographic names (continents, countries, states, cities, oceans, rivers, mountains, lakes, harbors, and valleys).

Howard Pickering Great Britain
Chicago British
New York Harbor Gulf of Mexico
Rocky Mountains Florida
Aleutian Islands the Aleutian low

Capitalize the names of historic events and documents, government units, political parties, business and fraternal organizations, clubs and societies, companies, and institutions.

the Second Amendment the Civil War
Congress Bureau of Mines
Republicans Ministry of Energy

Capitalize titles of rank when they are joined to a person’s name, and the names of stars and planets. Note: The names earth, sun, and moon are not normally capitalized, although they may be capitalized when used in connection with other bodies of the solar system.

Professor Walker President Spanier
Milky Way Venus

Capitalize words named after geographic locations, the names of major historical or geological time frames, and most words derived from proper names. Note: The only way to be sure if a word derived from a person’s name should be capitalized is to look it up in the dictionary. For example, “Bunsen burner” (after Robert Bunsen) is capitalized, while “diesel engine” (after Rudolph Diesel) is not. Also, referring to specific geologic time frames, the Chicago Manual of Style says not to capitalize the words “era,” “period,” and “epoch,” but the American Association of Petroleum Geologists says that these words should be capitalized. I choose to capitalize them, as those who write in the geological sciences should by convention.

Coriolis force Fourier coefficients
English tweeds Walker Circulation
Hadley cell Petri dish
Boyle’s law Russell volumeter
Planck’s constant Klinkenberg effect
Middle Jurassic Period Mesozoic Era
the Industrial Revolution the Inquisitio

Capitalize references to temperature scales, whether written out or abbreviated.

10 oF Fahrenheit degrees
22 oC Celsius degrees

Capitalize references to major sections of a country or the world.

the Near East the South

Capitalize the names of specific courses, the names of languages, and the names of semesters.

Anatomy 20 Russian
Spring semester 2009 Fall term, 2006

Common Capitalization Errors

Just as important as knowing when to capitalize is knowing when not to. Below, I set forth a few instances where capital letters are commonly used when they should not be. Please review this advice carefully, in that we all have made such capitalization errors. When in doubt, simply consult a print dictionary.

Do not capitalize the names of the seasons, unless the seasons are personified, as in poetry (“Spring’s breath”). (It is, of course, highly unlikely that you would personify a season in a technical paper.)

spring winter

Do not capitalize the words north, south, east, and west when they refer to directions, in that their meaning becomes generalized rather than site-specific.

We traveled west. The sun rises in the east.

In general, do not capitalize commonly used words that have come to have specialized meaning, even though their origins are in words that are capitalized.

navy blue india ink
pasteurization biblical

Do not capitalize the names of elements. Note: This is a common capitalization error, and can often be found in published work. Confusion no doubt arises because the symbols for elements are capitalized.

tungsten nitrogen
oxygen californium

Do not capitalize words that are used so frequently and informally that they have come to have highly generalized meaning.

north pole big bang theory
arctic climate midwesterner

Spelling

To understand the limited power of the spell checker, enjoy the following poem, which has an intriguing literary history:

I have a spelling checker
It came with my PC;
It plainly marks four my revue
Mistakes I cannot sea.
I've run this poem threw it,
I'm sure your pleased too no,
Its letter perfect in it's weigh,
My checker tolled me sew.

Just as so many of us rely on calculators to do all our math for us—even to the point that we do not trust calculations done by our own hand—far too many of us use spell checkers as proofreaders, and we ultimately use them to justify our own laziness. I once received a complaint from an outraged professor that a student had continually misspelled “miscellaneous” as “mescaline” (a hallucinogenic drug). The student’s spell checker did not pick up the error, but the professor certainly did, and he told me that he even speculated privately that the student who wrote the paper did so while on mescaline.

So proceed with caution when using spell checkers. They are not gods, and they do not substitute for meticulous proofreading and clear thinking. There is an instructive moment in a M*A*S*H episode, when Father Mulcahy complains to Colonel Potter about a typo in a new set of Bibles—one of the commandments reads “thou shalt commit adultery.” Father sheepishly worries aloud that “These lads are taught to follow orders.” For want of a single word the intended meaning is lost. Always proofread a hard copy, with your own two eyes.

Six Rules for Spelling

I have a crusty old copy of a book called Instant Spelling Dictionary, now in its third edition but first published in 1964, that I still use frequently. I adapted the six basic spelling rules that appear below from that dictionary. Even without memorizing the rules, you can improve your spelling simply by reviewing them and scanning the examples and exceptions until the fundamental concepts begin to sink in. When in doubt, always look up the word. And do not forget that desktop dictionaries work just as well as electronic ones.

Rule 1. In words ending with a silent "e," you usually drop the "e" before a suffix that begins with a vowel.

 

survive + al = survival
divide + ing = dividing
fortune + ate = fortunate

 

Common Exceptions:

 

manageable singeing mileage
advantageous dyeing acreage
peaceable canoeing lineage

 

Rule 2. In words ending with a silent "e," you usually retain the "e" before a suffix than begins with a consonant.

 

arrange + ment = arrangement
forgive + ness = forgiveness
safe + ty = safety

 

Common Exceptions:

 

ninth (from nine) argument (from argue)
wisdom (from wise) wholly (from whole)

 

Rule 3. In words of two or more syllables that are accented on the final syllable and end in a single consonant preceded by a single vowel, you double the final consonant before a suffix beginning with a vowel.

 

refer + ing = referring
regret + able = regrettable

 

However, if the accent is not on the last syllable, the final consonant is not doubled.

 

benefit + ed = benefited
audit + ed = audited

 

Rule 4. In words of one syllable ending in a single consonant that is preceded by a single vowel, you double the final consonant before a suffix that begins with a vowel. (It sounds more complex than it is; just look at the examples.)

big + est = biggest
hot + er = hotter
bag + age = baggage

Rule 5. In words ending in "y" preceded by a consonant, you usually change the "y" to "i" before any suffix that does not begin with an "i."

 

beauty + ful = beautiful
accompany + ment = accompaniment
accompany + ing = accompanying (suffix begins with i)

 

If the final "y" is preceded by a vowel, however, the rule does not apply.

journeys obeying essays
buys repaying attorneys

Rule 6. Use "i" before "e" except when the two letters follow "c" and have an "e" sound, or when they have an "a" sound as in "neighbor" and "weigh."

 

i before e (e sound) e before i (a sound)
shield vein
believe weight
grieve veil
mischievous neighbor

 

Common Exceptions:

 

weird foreign forfeit
either ancient neither
sovereign siege height
seize surfeit leisure

 

Everyday Words that are Commonly Misspelled

If you do find yourself over-relying on spell checkers or misspelling the same word for the 17th time this year, it would obviously be to your advantage to improve your spelling. One shortcut to doing this is to consult the following list of words that are frequently used and misspelled. Many smart writers even put a mark next to a word whenever they have to look it up, thereby helping themselves identify those fiendish words that give them the most trouble. To improve your spelling, you must commit the words you frequently misspell to memory, and physically looking them up until you do so is an effective path to spelling perfection. 

A

abandon
abandoned
abundant
absence
academic
academically
accelerator
accept
acceptable
accessible
accidentally
accommodate
accompanied
accompanying
accomplish
accumulate
accuracy
accustomed
achievement
acknowledge
acknowledgment
acquaintance
acquire
acquit
acre
acreage
across
actually
address
admission
admittance
adolescent
adolescence
advantageous
advertisement
aerial
against
aggravate
aggressive
aisle
a lot (never alot)
allotting
almost
already
always
amateur
among
amount
analysis
analyze
ancestry
announcement
annual
apparatus
apparent
apparently
appearance
appreciate
appropriate
appropriately
approximate
approximately
arctic
arguing
argument
article
artistically
association
athlete
athletic
attendance
attitude
awful
awkward

B

balance
bankruptcy
bargain
basically
battalion
beautiful
becoming
before
beginning
believe
beneficial
benefited
biased
biggest
boundary
Britain
bulletin
bureaucratic
business

C

calendar
camouflage
candidate
career
careful
category
ceiling
challenge
channel
chaos
character
characteristics
chief
chiefly
choose
chose
chosen
clothes
clothing
coarse
column
coming
commercial
commission
commitment
committee
communism
communists
compel
compelled
competition
completely
concede
conceivable
condemn
condemned
conferred
confused
connoisseur
conscience
conscientious
conscious
consists
continuous
controlled
controlling
controversial
convenient
coolly
criticism
crowded
cruelty
curiosity
curriculum

D

dealt
deceive
decision
deferred
definite
definitely
definition
descend
description
desirable
desperate
develop
different
dilemma
disagree
disappear
disappoint
disapprove
disaster
disastrous
discern
discipline
discussion
dispel
disservice
dissipate
distinct
duly
during

E

echoes
efficiency
efficient
eighth
eliminate
ellipse
embarrass
eminent
empty
endeavor
enemy
enthusiastically
entirely
entrance
environment
equipment
equipped
especially
essential
except
excellent
excess
existence
experience
explanation
extremely

F

fallacy
familiar
family
fascinate
fascism
favorite
February
fiery
finally
financial
financially
fission
fluorine
foreign
foresee
foreseeable
forfeit
forty
forward
fourth
frantically
friend
fulfill

G

generally
genius
government
grammar
grammatically
grandeur
Great Britain
grievance
guarantee
guerrilla
guidance

H

handicapped
happily
harass
heard
height
here
hindrance
hoping
hopeless
humorous
hundred
hurriedly
hygiene
hypocrisy
hypocrite

I

ideally
ignorant
illogical
imagine
imitate
immediately
immense
impossible
incidentally
independent
individually
ingenious
initially
initiative
innocent
innocuous
inoculate
intellectual
intelligence
intelligent
insistent
interest
interfered
interference
interrupt
iridescent
irrelevant
irreplaceable

J

jewelry
judgment
judicial

K

knowledge
knowledgeable

L

laboratory
later
lenient
liable
liaison
library
lightning
likely
listening
literature
loneliness
loose
lose
lying

M

magazine
maintenance
manageable
maneuver
manner
manual
marriage
mathematics
meant
medicine
medieval
mileage
millennium
miniature
miscellaneous
mischievous
missile
misspelled
mortgage
muscle

N

narrative
naturally
necessary
necessity
nineteen
ninety
ninth
noticeable
noticing
nuclear
nuisance
numerous

O

occasion
occasionally
occur
occurred
occurring
occurrence
official
omission
omit
omitted
oneself
operate
opinion
opponent
opportunity
opposite
oppression
ordinarily
originally

P

pamphlet
paraffin
parallel
parliament
particular
particularly
pastime
peaceable
peculiar
perceive
permissible
perseverance
persistence
pollute
pollution
population
possess
possession
possible
possibly
practically
preference
preferred
prejudice
prejudiced
primitive
privilege
probably
proceed
procedure
profession
professor
publicly
purpose

Q

quantify
quantity
quiet
quite

R

realize
rebellion
recede
receive
recession
recommend
reference
referring
remembrance
reservoir
rhythm
ridiculous

S

saccharine
sacrifice
safety
satellite
schedule
scientists
scintillate
separate
sergeant
shepherd
shining
shrubbery
similar
sincerely
sophomore
souvenir
specifically
statistics
strenuous
stretch
stubbornness
subtle
subtly
succeed
success
succession
succinct
sufficient
summary
summation
summed
supersede
supposed
suppress
surely
surprise
surrounding
syllable
symmetry
symmetrical

T

tariff
technique
temperament
temperature
their
therefore
thorough
though
through
tobacco
tomorrow
tragedy
transferred
trespass
truly
Tuesday
twelfth
tyranny

U

unanimous
unconscious
uncontrollable
undoubtedly
unforeseen
unmistakably
unnatural
unnecessary
until
usable
useful
usually

V

vacuum
valuable
various
vegetable
vehicle
vengeance
villain
violence
vicious
visible

W

warring
weather
Wednesday
weird
where
whether
whistle
wholly
whose
writing
written

Terms that are Commonly Misspelled in Technical Writing

 
A

abrasive
absorption
aggregate
Aleutian
algae
algorithm
alkali
alkyl
analogous
angular
anomalous
anomaly
aperture
aquatic
aqueous
aquifer
asbestos
asymmetry

B

bandwidth
base line
blackbody
brackish
buoyancy
buoyant

C

capacitance
Celsius
cetacean
chromatography
clear-cut
climatology
coaxial
combustible
condensation
conductivity
configuration
corollary
corrosion
crustacean
crustal
crystalline
crystallography

D

data base
deposition
desiccant
diffraction
diffusion
discrete
dissymmetry
divisible
Doppler effect
Doppler radar
drainage

E

ebullient
ebullition
eigenfunction
eigenvalue
emission 
emissivity
end point
equilibrium
equinox
evaporation
eyepiece

F

facies change
Fahrenheit
feedback
ferromagnetism
ferrous
filterable
flow chart
fluorescence
fluorescent
Fourier series
Fresnel equations

G

geyser
glacial
gradient

H

half-life
halogen
hatchable
heat-treat
histogram
histology
horsepower
hybridization
hydraulic
hysteresis

I

in situ
incandescent
infinitesimal
inflection
infrared
interference
isotropic
isotropism

L

least squares
logarithm
luminance
luminescence
luminescent
luminosity
luminous

M

manganese
mean life
measurable
metallurgical
metallurgy
midpoint
monetar

N

Newton's law
nucleation
nucle

O

opaque
operable
optical
orogeny
oscillation

P

parameter
peninsula
permeability
Petri dish
phosphorus
photo-ionization
photocell
piezoelectric
Planck's constant
plateau
polarization
polygon
polymerization
porosity
precipitation
predominant

R

radiant
radio frequency
radioactive
radiocarbon
refractive
resistant
resistivity
retardance
reversible
rock salt

S

salinity
seismic
side band
sinusoidal
solenoid
solid state
soluble
space-time
spectrometer
spectroscopy
steam-distilled
stochastic
strata
stratigraphic
stratigraphy
subsidence

T

terranes
test tube
tidal
tonnage
tornadoes
transit time
transmissible
transmissivity
transmittance
troposphere
trough
typhoon

U

unionized

V

valence
viscometer
viscosimeter
viscosity
viscous
visible

W

wave front
wave packet
wave system
wave theory
wavelength
wettability

X

xenolith

Self-Study

Word lists of additional commonly misspelled technical terms appear at these sites:

Extensive list of commonly misspelled technical terms

"A Short Guide to Technical Writing" page from the University of Utah