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Grammar, Punctuation, and Capitalization
A Handbook for Technical Writers and Editors
Mary K. McCaskill
"It is impossible to give rules that will cover every conceivable problem in capitalization" (G.P.O. 1984). Actually, what is capitalized is mostly a matter of editorial style and preference rather than a matter of generally accepted rules. In addition, although there is a clearly recognized rule requiring capitalization of proper nouns and adjectives, opinions differ concerning what a proper noun is.
First we should define terms used when discussing capitalization:
Elements in a document such as headings, titles, and captions may be capitalized in either sentence style or headline style:
Modern publishers tend toward a down style of capitalization, that is, toward use of fewer capitals, rather than an up style.
This chapter presents guidelines and Langley editorial preference for capitalization. There is so much difference of opinion among authorities as well as individuals concerning proper nouns and adjectives that total consistency among editors and authors is impossible. The important goal should be consistency within a particular document. The next three sections deal with the more clear-cut uses for capitalization; the last section deals with the most difficult area, proper nouns and adjectives.
It is second nature for us to capitalize the beginnings of such things as sentences, quotations, and captions. Rules hardly need to be expressed to cover these areas; however this section briefly addresses them and indicates Langley's preferred style.
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The first word in a sentence is ordinarily capitalized.
A sentence enclosed in parentheses within another sentence does not begin with a capital:
In applying the foregoing approach to a tetrahedral grid (the tetrahedral grid was chosen because of its attractive features for space construction), a typical repeating element is first isolated from the grid.
However, a parenthesized sentence that does not stand within another sentence begins with a capital:
The foregoing approach is now applied to a tetrahedral grid. (The tetrahedral grid was chosen because of its attractive features for space construction.) A typical repeating element is first isolated from the grid.
In the rare instances that fragment sentences may appear in a document, they should begin with a capital:
Can system identification procedures be applied to statically unstable aircraft? if so, to which aircraft?
Can system identification procedures be applied to statically unstable aircraft? If so, to which aircraft?
The first word after a colon may be capitalized when the capital begins a complete sentence; however, capitalization of a complete sentence after a colon is optional:
The toughness of pseudo-maraging steel degrades at cryogenic temperatures: At -320°F, its Charpy impact energy is 6 ft-lb.
The toughness of pseudo-maraging steel degrades at cryogenic temperatures: at -320°F, its Charpy impact energy is 6 ft-lb.
The beginning of quoted material is capitalized as follows:
A direct quotation that is not syntactically joined to the rest of the sentence (often set off by commas) begins with a capital, even if the initial letter is not capital in the source (Chicago Press 1982; and Skillin et al. 1974):
In the law establishing the NACA, Congress states: "It shall be the duty of the Advisory Committee for Aeronautics to supervise and direct the scientific study of the problems of flight with a view to their practical solution."
When the quote is syntactically dependent on the rest of the sentence, it begins with a lowercase letter, even if the initial letter is capital in the source:
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Congress established the NACA in 1915 "to supervise and direct the scientific study of the problems of flight with a view to their practical solution."
When ellipsis points in a quotation follow a period (that is, four dots), the first word of the sentence following the ellipsis may be capitalized, even if it is not capital in the source:
"The airplane then accelerated to a Mach number of 0.98. . . . The needle of the Mach meter took an abrupt jump past M = 1.0."
When a direct question occurs within a sentence, the author may or may not choose to capitalize the first word of the question:
The question addressed by this research project is, What system identification procedure should be used for a statically unstable aircraft?
The question addressed by this research project is, what system identification procedure should be used for a statically unstable aircraft?
Of course, an indirect question is never capitalized:
This research project addresses what system identification procedure should be used for statically unstable aircraft.
Items in a displayed list should begin with a capital whether they are complete sentences or not:
The purposes of this report are
- To evaluate the performance of the instruments
- To expand the data base
We can define the requirements of the power converter as follows:
- Energy conversion should be high.
- Efficiency should be independent of laser wavelength.
Support systems for the facility supply the following:
- Air--The 600-psi system can deliver a flow rate of 300 lb/sec for 3 min.
- Cooling water--The closed-loop system delivers 450 gal/min at 550 psig.
- Gaseous propellants--Hydrogen, oxygen, and nitrogen are supplied from 60 000-ft3 tube trailers at 2400 psia.
Skillin et al. (1974) indicate that capitalizing nonsentence displayed items is optional, but we prefer the capitals. When lists are not displayed, the items are, of course, not capitalized:
The purposes of this report are (1) to evaluate the performance of the instruments and (2) to expand the data base.
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Nonsentence elements, such as table entries, captions, or footnotes, are often capitalized as a matter of style. The following elements are capitalized in sentence style in Langley reports:
Table subtitles, headnotes, boxheads, and entries consisting of words, phrases, or sentences
Footnotes to either the text or a table
Figure 1. Three-view sketch of the research aircraft. Dimensions are in inches.
Figure 1. Computing scheme for algorithm.
Figure 1. Concluded.
Figure labels (we prefer initial cap over full caps or caps & lc for labels in figures)
A word or phrase appearing in a symbolic expression:
Headline style calls for all principal words to be capitalized (also called caps & lc). Unfortunately authorities differ widely on what words are principal. Langley rules for headline style capitalization are based on the G.P.O. (1984) and are as follows:
Do not capitalize the articles a, an, and the; the prepositions or adverbs at, by, for, of, in, up, on, and to; and the conjunctions and, as, but, if, or, and nor. In effect, this rule means that words of four or more letters are considered principal words and are capitalized.
Capitalize the first and last words:
Capitalize both elements of a two-element hyphenated compound word except the second element of a compound numeral:
Vapor-Screen Systems for In-Flight Flow Visualization
Evaluation of Twenty-one
High-Resolution Graphics Work Stations
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In a hyphenated phrase of three or more words, the first element and other elements that are principal words are capitalized (Skillin et al. 1974):
If a normally lowercase short word is used parallel with a capitalized word of like significance, the short word should be capitalized:
Capitalize the infinitive to (note that some authorities, for example, Chicago Press 1982, recommend lowercase for the infinitive):
Toughness of High-Strength Steels
Grain-Refining Heat Treatments
Resulting in Improvements to Cryogenic
Toughness of High-Strength Steels
Normally lowercase abbreviations should always be left lowercase, particularly abbreviations for units of measure:
Toughness of 0.5-cm-Thick Specimens
Noise Exposure From 10:00 p.m. to 6:00 a.m.
Headline style capitalization is used for proper nouns (see section 4.5).
As a matter of preferred style, the following elements are capitalized in headline style in Langley reports:
Displayed (not run-in) headings
Table IV. Concluded
Before beginning a discussion of capitalization of abbreviations and acronyms, the two must be clearly distinguished. An abbreviation is a shortened version of a word or phrase and is often followed by a period, for example, c.o.d., ft-lb, St.,or publ. Abbreviations usually have become standard so that their form can be looked up in a reference book. Acronyms, on the other hand, are "words formed from the initial letters of successive parts of a term" (Skillin et al. 1974), for example, NASA, NASTRAN, STIF, NASP. They never contain periods and are often not standard, so that definition is required.
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Acronyms are always formed with capital letters. A few words have crept into our language which were initially acronyms, for example, laser and radar. But generally acronyms remain in full caps.
Acronyms are often coined for a particular program or study and therefore require definition. The letters of the acronym are not capitalized in the definition unless the acronym stands for a proper name:
The best electronic publishing systems combine What You See Is What You Get (WYSIWIG) features with the power of noninteractive text formatters.
The best electronic publishing systems combine what you see is what you get (WYSIWIG) features with the power of noninteractive text formatters.
Langley is involved with the National Aero-Space Plane (NASP) Program.
Nor is it usually necessary to indicate, for example, with italics, which letters are used in the acronym.
"In general, an abbreviation follows the capitalization ... of the word or words abbreviated" (G.P.O. 1984). The best way to determine the form of an unfamiliar abbreviation is to consult a reference, for example,
Webster's Collegiate or Unabridged Dictionary
G.P.O. Style Manual
In material such as titles or headings in which principal words are capitalized (caps & lc), normally lowercase abbreviations should always be left lowercase, particularly abbreviations for units of measure:
Toughness of 0.5-cm-Thick Specimens
Noise Exposure From 10:00 p.m. to 6:00 a.m.
As mentioned in the Introduction to this chapter, there is a clearly recognized rule requiring capitalization of proper nouns and adjectives. The problem is that no one agrees on exactly what constitutes a proper noun. Proper nouns are defined as "the name of a particular person, place, or thing." Thus, the names of such things as organizations, political divisions, calendar divisions, and historic events and holidays are capitalized just as personal names and geographic names are.
Whether or not a particular word or phrase is a proper noun is often a matter of opinion. Langley follows the current trend and prefers a down style, that is, fewer capitals. The following sections provide guidelines; if difficulty arises over a particular noun, consult references such as a dictionary, Skillin et al. (1974), G.P.O. (1984), or Chicago Press (1982).
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In general, proper nouns and derivatives of proper nouns used in a proper sense are capitalized:
Roman (of Rome)
However, derivatives of proper nouns that have acquired an independent meaning are not capitalized:
pascal (the unit)
"Defining the distinction between proper adjectives with a proper meaning and derivatives ... with a common meaning is sometimes difficult" (Skillin et al. 1974):
G. B. Venturi
The dictionary is a good reference for guidance in this matter, but is not always definitive. For example, in Webster's Ninth New Collegiate Dictionary, euclidean geometry has the label "often cap E," which means that "it is as acceptable with an uppercase initial as it is with one in lowercase." Thus, usage in the given field and author preference should prevail.
A common noun in a proper name is capitalized, but not when used alone:
The experimental investigation was conducted in the Langley 16-Foot Transonic Tunnel. This single-return tunnel has continuous air exchange.
However, when a common noun alone becomes a well-known short from for the proper name, it is capitalized:
United States, the States
U.S. Army, the Army
President of the United States, the President
The plural form in a proper name is capitalized (G.P.O. 1984):
Seventh and Ninth Streets
Lakes Eerie and Ontario
Langley 16-Foot and 30- by 60-Foot Tunnels
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A common noun used with a number or letter for purposes of designation is not capitalized (G.P.O. 1984):
Only when the word the is part of an official name is it capitalized:
The College of William and Mary
the National Aeronautics and Space Administration
Rarely is there any question concerning capitalization of personal names.
In foreign names, particles such as d', de, du, and von are capitalized unless preceded by a forename or title:
E. I. du Pont
Theodore von Karman
Von Karman Institute
Remember that a personal name that is used in a common sense is no longer capitalized:
the units curie, watt, newton, and kelvin
Civil and professional titles are capitalized when they precede a personal name as part of the name (Chicago Press 1982):
Chief Scientist Barnwell
Such titles are not capitalized in apposition however:
the chief scientist, Richard Barnwell
the chief of Materials Division, Darrel Tenney
Civil and professional titles following or in place of a personal name are rarely capitalized (Chicago Press 1982):
Richard Petersen, director of Langley Research Center; the director
A. J. Hansbrough, chief of the Research Information and Applications Division; the division chief
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Perry Deal, chief test pilot
Richard A. Culpepper, test director; the test director
But, to indicate distinction, a common noun title after a name is capitalized (G.P.O. 1984):
Ronald Reagan, President of the United States
In a document to a very specific audience, a common noun used as part of or in place of a personal name may be capitalized (Skillin et al. 1974). Thus, in a Langley memo, letter, or internal document, such titles as Director, Associate Director, Division Chief, and Branch Head may be capitalized.
The names of particular regions, localities, countries, and geographic features are capitalized:
Names of geographic features
Tropic of Cancer
Tropic of Cancer
Names of regions and localities
North Atlantic States6
North and South (Civil War Period)
eastern Gulf states
Directions of the compass are capitalized only as a part of a name that has been established by usage to designate particular regions.
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Names of rivers, mountains, bays, and cities
San Francisco Bay
Del Marva Peninsula
New York City
The satellite orbit often crossed the Sahara Desert. In parts of this desert, seasonal transitions occur between desert and vegetated land.
When generic terms such as lake, city, and river are used to refer to a specific place, they are still lowercase except in a few established instances:
the Canal (Panama Canal)
the Channel (English Channel)
Official designations of political divisions and of other organized bodies are capitalized:
Names of political divisions
New York State
Names of governmental units
Environmental Protection Agency
Technical Editing Branch
Names of organizations and their members
Democratic Pary, Catholic Church
a Democrat, a Catholic (members)
Democratic administration, Catholic doctrine
Society of Automotive Engineers
democratic government (a democracy)
catholicity (character of being liberal)
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The proper names of public places, facilities, and structures are capitalized:
Langley Research Center
National Transonic Facility
H. J. E. Reid Auditorium
The names of permanent research facilities at Langley Research Center (and other institutions) are capitalized, but not temporary (that is, not officially permanent) apparatuses and facilities:
Langley Aircraft Landing Dynamics Facility
Langley 55-Foot Vacuum Chamber
neutron generator at the Langley Research Center
outdoor anechoic test apparatus at the Langley Research Center
Various holidays, historic events, and other time designations are capitalized:
Names of months and days of the week
But seasons are not capitalized:
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Time zones are not capitalized:
eastern standard time
mountain daylight time
Greenwich mean time
Pacific standard time
In several scientific disciplines, there are conventions for capitalization of names, for example, the names of celestial bodies in astronomy and the names of soil groups in geology.
Upper Cambrian Period, Bronze Age (geologic periods)
Laterite, Tundra (soil groups)
Names of celestial bodies
North Star, Halley's Comet
Venus, Earth (the planet)
the Sun, the Moon (Earth's)
earth (the ground)
moons of Jupiter
Consult CBE (1978) or other specialized references for details of capitalization of biological names.
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Titles of written and artistic works are capitalized.
Declaration of Independence
Treaty of Paris
Titles of documents, essays, and articles
Slater, Philip N. 1980: Remote Sensing--Optics and Optical Systems. Addison-Wesley Publ. Co., Inc.
Elterman, L. 1970: Vertical-Attenuation Model With Eight Surface Meteorological Ranges From 2 to 14 Kilometers. AFCRL-70-0200, U.S. Air Force, Mar. (Available from DTIC as AD 707 488.)
Bowker, D. E.; Davis, R. E.; Von Ofenheim, W. H. C.; and Myrick, D. L. 1983: Estimation of Spectral Reflectance Signatures From Spectral Radiance Profiles. Proceedings of the Seventeenth International Symposium on Remote Sensing of the Environment, Volume II, Environmental Research Inst. of Michigan, pp. 795-814.
Allen, William A.; and Richardson, Arthur J. 1968: Interaction of Light With a Plant Canopy. J. Opt. Soc. America, vol. 58, no. 8, Aug., pp. 1923-1928.
Note that a down style of capitalization for titles (Chicago Press 1982) is recommended by some publishers. We prefer an up style.
Names of computer programs that are published (for example, in COSMIC):
Optimal Regulator Algorithms for the Control of Linear Systems (ORACLS)
Interaction of Structures, Aerodynamics, and Controls (ISAC)
Aircarft Noise Prediction Program (ANOPP)
extended least squares algorithm (module of ISAC)
optimization algorithm (in ORACLS)
Freedom of Information Act
Executive Order No. 24
Public Law 271
Works of art and music
Blue Boy, Whistler's Mother
Star Spangled Banner
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The following are additional types of proper names:
Races and tribes
Note: To protect the owners of trade names, they should be used only as adjectives. Also, NASA's policy is to list the owner of a trade name, if the trade name is given at all.
Official names of research missions, programs, and vehicles
Aircraft Energy Efficiency Program
Space Station Freedom
a space shuttle (generic sense)
Space Shuttle orbiter and external tank
Langley basic research program (not official name)
space station (generic sense)
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