• abbreviations (See also acronyms.)
  When in doubt, spell it out. The current trend is not to use periods in abbreviations: GPA, EOP, UN, NATO, CIA. Here are some exceptions: B.A., Ph.D., U.S., D.C., L.A., M.D., Mrs., etc., St., Co., pp. Note that you should insert a letter space between the initials in a proper name: E. B. White. In general, avoid "alphabet soup." Do not use abbreviations or acronyms that the reader would not quickly recognize.

• accent marks
  Use with foreign words such as "café" or "cliché."

• acronyms
  Always spell out the full name or phrase the first time, followed by the acronym in parenthesis; then use the acronym alone in subsequent references: "The Aztec Parents Association (APA) met in January. The APA is expected to meet again in June." Exceptions are extremely well-known acronyms such as NAACP, NASA, FBI, etc. Use GPA, not G.P.A.

• ages
  Always use figures. The boy is 5 years old; the 9-year-old girl lives here; the woman is in her 30s.

• ageism (See inclusive language.)

• a.m., p.m. (See also time.)
  Lowercase and use periods.

• ampersand (&)
  Avoid unless part of an official name.

• apostrophes (See also plurals and possessives.)
  • To show possession, add an apostrophe and letter "s" to singular words, even if they end in s or z:
    • campus's
    • Liz's
    • Dickens's
  • To plurals ending in s, add an apostrophe only:
    • nine dogs' tails
  • Don't confuse possessive adjectives, which do not take apostrophes, with contractions, which do:
    • The cat lost its toy.
    • It's time to go.
  • Omit the apostrophe from plurals:
    • 1990s
    • POWs
    • M.A.s and Ph.D.s
  • Words as words (do not use an apostrophe):
    • His argument had too many "ifs" and "maybes" to sound convincing.

• biased language (See inclusive language.)

• brackets
  Use brackets to add explanations or corrections to quoted material: "He [John Smith] received his diploma yesterday," said the chancellor. Use brackets as parentheses within parentheses: "You can learn about the process of writing a play by reading a collection of interviews with playwright Tony Kushner (Robert Vorlicky, ed. Tony Kushner in Conversation [Ann Arbor, Mich.: The University of Michigan Press, 1998])."

• bullets
  Bulleted items that conclude an introductory sentence should be lowercase and punctuated with a comma or semicolon at the end of each item except for the last. Use the word "and" before the last bulleted item, and end the sentence with a period: When each item of a list completes the introductory sentence,
  • list items should begin with lowercase letters;
  • all but the last item should end with a comma or semicolon;
  • the second-to-last item ends with "and"
  • the last item ends with a period.

  Bulleted items that are not part of an introductory sentence may be upper- or lowercase and may end with either periods or no punctuation. However, format should be consistent within any given context:

  San Diego area residents enjoy a variety of seasonal recreational activities:

  • water sports
  • camping and hiking
  • skiing
  • picnicking
    
    

  Usually, there is a space between the bullet and the first word of each item.

• capitalization
  For pointers, see the Purdue University Online Writing Lab section on capitalization. The following examples serve as general guides to capitalization:
  
  
  University or university (See SDSU-specific Guidelines: Capitalization Notes.)
  
  city of San Diego
  county of Los Angeles
  San Diego County
  San Diego Area
  Sacramento Valley
  San Francisco Bay Area
  San Joaquin Valley
  San Diego City Council; the city council
  federal
  U.S. government
  Bush administration
  state of California
  state Department of Health
  U.S. Department of State
  New York State
  The state is experiencing a surplus.
  
  Earth (planet)
  Central Coast
  Central Valley
  southern California
  south Georgia
  the South
  the South Bronx
  Southern Hemisphere
  North Africa
  Pacific Northwest
  western Asia
  Southeast Asia
  central Africa
  Eastern philosophy
  eastern U.S.
  We walked east.
  East Coast
  
  African American, Asian American, Mexican American, Native American,
  Euro-American, Hispanic, Chicano, Latino, black, white
  Note also the adjectival forms:African American student,
  Euro-American student, Italian American neighborhood
  
  biblical (lower case)

• centuries
  Except at the beginning of a sentence, use figures in ordinals (20th century). Hyphenate when used as a compound adjective (19th-century novels). No apostrophe in such designations as 1900s. Centuries: lowercase, spelling out centuries under 10: ninth century but 10th century.

• chair
  (See entry in General Academic Usage.)

• colon (See also semicolon.)
  Use a colon to introduce a list or series: "The president mentioned three possible candidates for the award: Johnson, Phillips, and Vandever."
  
  Do not use a colon between a verb and its complement or object: "The three candidates are: Johnson, Phillips and Vandever."
  
  Use a colon to introduce word groups that begin with for example, for instance, that is, and namely: "American history courses often discuss some of our nation's most famous documents: for example, the Constitution and the Declaration of Independence."

• comma (See also semicolon.)
  For dates and times, use the following guidelines:

April 1, 1950, was. . . .
April 1950 was. . . .
The program is scheduled for 8:30 p.m., Tuesday, December 12, 2000.

Commas in digits signifying thousands (1,500 vs. when not to use them, i.e., 1500 degrees)

A word, phrase or clause that is in apposition to a noun and that is parenthetical is set off by commas:

Washington, D.C., is. . . .
My husband, Joe, studies. . . .

If, however, the word, phrase or clause is restrictive (identifies or restricts the meaning of the noun), commas should not be used:

My sister Ellen works. . . .(the speaker has more than one sister)
Milton's work Paradise Lost was. . . .
The book that I received for Christmas . . . (use "that," not "which," in restrictive clauses).

In a series or list: use commas to separate elements in a series, but do not place a comma before the conjunction in a simple series:

She'd ordered chicken marsala, salad and white wine.
The house was painted sea green, cream and tan.

Use a comma before a conjunction connecting two independent clauses:

Course 20 is required for the major, and students should complete it by the end of their junior year.

As a general rule, do not use a comma before a conjunction connecting a compound predicate:

Joe bought two books and looked at the magazines.

• dash
  There are two kinds of dash-of different length and for different purposes-in addition to the hyphen. The em dash (-) is the true dash, used for parenthetical remarks or abrupt changes of thought, epigraphs, and datelines. Because there was no dash character on a typewriter keyboard, dashes were traditionally indicated by two hyphens (--). Computers offer typists the ability to produce a proper dash. Newspapers traditionally used a space on each side of a dash, and AP still requires such spaces. However, letter spacing is the responsibility of the designer (of the typeface and of the publication), and it is not necessary to routinely add such spaces. Columns do not use spaces around dashes. The em dash is named for the amount of letter space, that of a capital M, that it occupied in a line of type set in the particular typeface. The en dash (-) is shorter than the em dash and longer than a hyphen. It is used for continuing or inclusive numbers or words (range constructions: pages 7-10; Jan. 5-9; E-P; Monday-Friday), but not when the word "from" is actually used (1968-72 or from 1968 to 1972, never from 1968-72). An en dash is also used in place of a hyphen in a compound adjective when one of the elements is an open compound (post-Civil War; Peabody Award-winning program, Athens-Clarke County government).

• dates
  Use commas to set off the year when using full dates:
  

She graduated on May 18, 2001, in San Diego.
April 1, 1950, was. . . .
April 1950 was. . . .
Planning began in September 1985.
The program is scheduled for 8:30 p.m., Tuesday, December 12, 2000.
Do not use 1st, 2nd, etc., with dates: July 21, April 2, etc. (not July 21st, April 2nd, etc.)

Specify the year only if not the current calendar year:

John and Joan Jones had a baby in December 2001; or The Smiths had a baby in January.

(See also entries for "academic years," "centuries," "decades," "months" and "years".)

• decades
  No apostrophe in decades (1980s). Use an apostrophe (not open single quotation mark) to replace the first two digits if they are omitted ('80s). "The air temperature was in the 90s throughout the '90s when she was in her 90s." (See also entries for "academic years," "centuries," "dates," "months" and "years".)

• disabilities, writing about people with: (See inclusive language.)

• e.g./i.e. (See i.e./e.g.)

• ethnicity (See inclusive language.)

• exclamation point
  Use the mark to express a high degree of surprise, incredulity or other strong emotion. Avoid overuse.
  
  Placement with quotes: Place the mark inside quotation marks when it is part of the quoted material: " That's great!" he shouted.
  
  Place the mark outside the quotation marks when it is not part of the quoted material: I hated reading Melville's "Bartleby the Scrivener"!

• figures
  Use numerals for numbers 10 or greater; spell out zero up to and including nine:

  one, eight, nine
  10, 21, 105, 2,436

  EXCEPTIONS: use figures for degrees (temperature or longitudinal). Spell out any number at the beginning of a sentence: Twenty years ago today, Sgt. Pepper...
  
  Use a comma with numerals of 1,000 and above (except dates): 5,000, 42,000.
  
  Exceptions to the rules:

  • Use numerals when referring to academic credit: The student earned 2.5 hours of credit.
  • Use numerals when referring to a page number: The passage begins on page 5.
  • Numbers may be mixed in the same sentence or paragraph: SDSU had two administrators and 11 faculty giving reports. Eleven journalists, three legislators, and 146 community members voiced their opinions.
  • Use the same rules for ordinal numbers:

    second, ninth, 10th, 25th, 169th
    
    UCSC's five tennis players ranked first, third, 10th, l6th, and 23rd in the men's singles competition.

  • In scientific text physical quantities, such as distances, lengths, or areas, should be expressed in figures; in ordinary text such quantities should be treated according to the rules above.
  • Ages always use figures: The boy is 5 years old; the 9-year-old girl lives here. (See ages.)
  • Use figures for course numbers, scores, percentages, compound numbers, decimal fractions,and very large numbers:

    Biology 3
    5 percent (See percent.)
    4 feet 7 inches
    1.34
    $5 billion
    3 million years ago
    

  • Dates (See dates.)
    
    
  • Page numbers always use figures: The footnote was on page 7.
    
    
  • Plus mark: avoid it (say 30-plus, not 30+).
    
    
  • Fractions: Spell out amounts less than 1, using hyphens between the words: two-thirds, seven-sixteenths, etc.
    
    
  • Time of day (See time.)

• fund-raising, fund raising, fund-raiser
  ("Many agree that fund raising is difficult. They planned a fund-raising campaign and hired a new fund-raiser.")

• gender (See inclusive language.)

• geographic regions
  Lowercase north, south, northeast, northern, etc., when they indicate compass direction. Capitalize these words when they refer to a region:
  

Many industries are relocating to the South.

Other examples:

• Most publishing companies are based on the East Coast.
  He is a Midwesterner.
  The Southwest generally is hot and dry all year.
• With names of nations: Lowercase unless they are a part of a proper name or are used to designate a politically divided nation:

  southern France
  the western United States
  But: Northern Ireland, Northwest Territories

• hyphens
  Hyphenate any modifying words combined with WELL when preceding a noun (well-built engine, well-grounded in mathematics). Do not hyphenate words with the prefix NON, PRE, SEMI, ANTI, or CO, except those containing a proper noun (e.g., nonprofit, premedical, non-German). Exception: hyphenate to avoid duplicated vowels or triple consonants (pre-enroll, bell-like). Suspensive Hyphenation: the loan was offered for a 10- to 15-year period; both full- and part-time jobs were offered.
  
  Words formed with prefixes are not usually hyphenated:
  
  

  prewar, nonprofit
  

  Exceptions: when the second element is capitalized, when the second element is a figure, or to distinguish homonyms:

  pre-Civil War
  pre-1960
  re-create, un-ionized

  Many compounds that are spelled open as nouns are hyphenated as adjectives:

  field-study program
  high-level job
  long-range planning
  lower-division course
  ninth-century manuscript
  off-campus housing

  
  Compounds that begin with adverbs ending in -ly are spelled open:

  highly complex species
  poorly organized paper

  
  Use this form for compound hyphenation:

  two- to three-semester program
  

  Here are our preferred forms of some commonly used compounds and other terms:

  • audiovisual (or audio-visual)
  • bilingual
  • campuswide
  • coauthor
  • co-op, cooperative
  • copy edit
  • cross-cultural
  • database
  • decision making
  • e-mail
  • fax
  • field house
  • field study
  • fieldwork
  • freelance
  • full time, full-time
    He works full time. Hyphenate only when used as a compound modifier: She got a full-time job.
  • fundraising, fundraiser
  • groundbreaking
  • interdisciplinary
  • midcentury
  • mid-June
  • multicultural
  • nonmajor, nonresident
  • off-campus (adj.), off campus (adv.)
    Hyphenate when used as an adjective: The university is looking at off-campus housing as an option. Write two words, without hyphenation when used as an adverb: The student moved off campus. Guidelines are the same for on-campus and on campus.
  • online, offline
  • part time, part-time
    She works part time. Hyphenate only when used as a compound modifier: He has a part-time job.
  • postdoctorate
  • postgraduate
  • pre-enrollment
  • prelaw, premedicine
  • re-enter, re-entry
  • semiconductor
  • socioeconomic
  • statewide
  • systemwide
  • Third World
  • underrepresented
  • under way (adverb)
  • universitywide
  • Unix
  • up-to-date
  • work-study

• i.e./e.g.
  i.e. means that is. (Latin: "id est.")
  e.g. means for example. (Latin: "exempli gratia.")

• impact
  Do not use as a verb. Use affect or influence. "Failing biology affected his choice of a major," not "Failing biology impacted his choice of a major."

• inclusive language
  (See also SDSU Senate Policy File III-A-2: Statement on Diversity.)
  
  • ageism: Common stereotypes portray the old as foolish, frail, poor, isolated, rigid, reactionary, senile, or kind and grandparently. Avoid such stereotypes.
    
  • appearance: Avoid negative stereotypes of the obese and overweight. Characteristics such as lazy, stupid, sad or lacking willpower are sometimes attributed on the basis of body shape and size alone. Alternatively, the association in the media of thinness with desirable characteristics such as happiness, acceptance and self-confidence is a model that should not be followed. Irrelevant descriptions of women's appearance and attire should be edited out.
    
  • disabilities: The term "disabled" is preferable to "handicapped." The phrase "people with disabilities" is preferable to "the disabled." Write "He has muscular dystrophy" rather than "He is afflicted with" or "is a victim of." Write "She uses a wheelchair" or "walks with crutches" rather than "is wheelchair-bound" or "confined to a wheelchair." Handicapped is, however, still used for references to parking and building access.
  • race, ethnicity, nationality: Use white (not Caucasian). Lowercase blacks and whites but capitalize identifications with geographic words: American Indian or Native American, Asian (not Oriental), African Americans, Asian American, Chicano, Euro-American, Filipino, German American, Hispanic, Indians, Latino, Latina, Mexican American, Native Alaskan (never Eskimo), Native American, Pacific Islander. Say "international student" (not "alien" or "foreign"). Use "underrepresented" or "underserved" students; do not use the term "minority." Note also the adjectival forms:
    

    African American student
    Euro-American student
    Italian American neighborhood

  • sex and gender, sexual orientation
    Copy intended to apply to both sexes should be written so that no gender bias is suggested. Avoid man, mankind, and words ending in -man. Substitute: humanity, people, worker, firefighter, etc. Avoid singular pronouns (he, she, his, hers) when referring to both sexes. Substitute they or you:

  
  Students pay their fees . . .
  You should pay your fees . . .
  (not "a student should pay his fees . . . )

  If absolutely necessary, both pronouns can be used with or (do not use he/she or his/her): A student should pay his or her fees. . .

  Lady/woman: Use woman when referring to a female 18 years or older.

  Sexual orientation: "Gay" is acceptable as a popular synonym for both males and females, although it is generally associated with males, while "lesbian" is the more common term for homosexual females. Avoid references to gay, homosexual or alternative "lifestyle." Use "sexual orientation," not "sexual preference."

• italics
  Italicize names of books; journals; magazines and similar periodicals; plays; long poems and collections of poetry; names of drawings, paintings, photographs, statues and other works of visual art; specific names of boats, ships, submarines, aircraft, airplanes, spacecraft; scientific names of plants and animals; isolated words or phrases in a foreign language (translations are enclosed in parenthesis) and words or phrases that are emphasized in textual material.
  

• junior (See titles, personal.)

• months
  Names of months are spelled out in text when they are not accompanied by a specific date. They are spelled out when accompanied by a year. Examples:

  The fall semester begins in August.
  In December 2000 Arkansas had a terrible ice storm.

The following months are abbreviated in text when accompanied by a date: Jan., Feb., Aug., Sept., Oct., Nov. and Dec. Examples:

The next club meeting is Monday, Nov. 12, 2001.
Graduation will be held on May 18, 2002.

(See also entries for "academic years," "centuries," "dates," "decades" and "years".)

• numbers, numerals (See figures.)

• OK, OK'd, OK'ing, OKs
  But not O.K. or okay.

• percent
  One word, spell out (avoid % except in tables and graphics).For amounts less than one percent, use a zero: "His GPA rose only 0.7 percent." Repeat the word "percent" with each additional figure in a sentence: "The professor noted that 7 percent to 12 percent of his students had failed the test."

• phone numbers (See telephone numbers.)

• plurals (See also apostrophes and possessives.)
  • Words ending in "ch," "s," "sh," "ss," "x" and "z," add "es" to form the plural: batches, lenses, marshes, masses, boxes, fizzes.
  • Words ending in "is," change the "is" to "es": analyses, theses, oases.
  • Words ending in "y" (if preceded by a consonant or "qu"), change the "y" to "i" and add "es": armies, ladies, sololoquies. Otherwise, add "s": keys, plays. (For proper names ending in "y," simply add "s": Kennedys, Murphys.)
  • Words ending in "o" (if preceded by a consonant), add "es": heroes, echoes. (Pianos is an exception.)
  • Words ending in "f," change the "f" to "v" and add "es": hooves, loaves. (Roofs is an exception.)
    

Omit the apostrophe from plurals:

1990s
POWs
M.A.s and Ph.D.s

Latin plurals:

Singular: criterion, medium, symposium
Plural: criteria, media, symposia

Use apostrophe with plural of single letters (She earned four A's and two B's), but not with multiple letter combinations (I know my ABCs) or with numerals.

• plus
  Don't use as a substitute for "also," "in addition" or "moreover."

• plus mark (+)
  Avoid it. Say 30-plus, not 30+.

• possessives (See also apostrophes.)
  Add an apostrophe and "s" to singular nouns not ending in "s": boy's friend, Karl Marx's book, Professor Smith's class.

Add an apostrophe and "s" to singular common nouns ending in "s" unless the next word begins with "s": the hostess's dress, the hostess' swimming pool.

Use only an apostrophe with singular proper names ending in "s": Dickens' book, Jesus' teachings.

Use only an apostrophe with words that don't end in "s" but that end in an "s" sound and are followed by a word beginning with "s": for appearance' sake, for conscience' sake. When such words are followed by a word not beginning with "s," use an apostrophe and "s."

Use a possessive form after the last word if ownership is joint (John and Georgia's chess game) and after both words if the objects are individually owned (Phil's and Ken's garages).

Use the possessive in cases like the following where the focus is on the activity, not the person: John's constantly playing Nintendo drives me bonkers. Dad doesn't approve of my betting on horses.

• quotations and block quotations
  In running text, quoted words, phrases and sentences are enclosed in double quotation marks: Holmes said, "My well of English seems to be permanently defiled." "He says" and all its variations are set off by commas from the quoted text: "My well of English," says Holmes, "seems to be permanently defiled."
  
  Quoted matter may stand by itself (as in the examples above) or be worked into your own sentence: Holmes says that his "well of English seems to be permanently defiled." Use single quotation marks for quotations within quotations: Watson says, "Sherlock Holmes once said, 'My well of English seems to be permanently defiled.'"
  
  The period and comma always go within the quotation marks. The dash, semicolon, question mark and exclamation point go inside when they apply to the quoted matter but outside when they apply to the entire sentence.
  
  When a quotation is longer than one paragraph, use quotation marks at the beginning of each paragraph but only at the end of the last paragraph.
  
  Block quotations
  Material set off from the rest of the text as a block quotation is indented, left and right, and not enclosed in quotation marks. Quoted matter included within a block quotation should be enclosed in double quotation marks.

• race/racial language (See inclusive language.)

• religious titles (See titles.)

• R.S.V.P.
  French, "répondez s'il vous plaît" (please reply).

• seasons
  Lowercase the names of the seasons unless they are part of a formal name or designate an issue of a periodical: Winter Olympic Games, the Fall 2000 issue of Poetry. He graduated in the spring semester. She arrived in time for fall 2000 registration. (See also General Academic Usage: semester.)

• semicolon (See also colon.)
  Use a semicolon to connect two *independent clauses if they are closely connected in meaning:
  "The girls played piano; the boys danced."
  "It was a great book; I read it in 2 hours."
  
  Use a semicolon between two *independent clauses when they are joined by a connecting word such as "however" or "therefore":
  "The movie was boring; nevertheless, I stayed awake."
  "I'll get you the money; however, you're going to have to pay me back."
  
  Use a semicolon in a serial list when separate elements of the list contain commas:
  She had two sons, Mark and Hank; three daughters, Jessica, Mary and Sara; and four grandchildren, Hanna, Laura, Kristina and Anika.
  

• sexist language (See inclusive language.)

• sic
  Use sic (which means "intentionally so written") in brackets to indicate that an error in the quoted material is being reproduced exactly: "He writes that he is a strong admirer of President Brush [sic]." Italicize sic; do not place a period after the letter "c."

• states
  Capitalize the names of states; lowercase the word state: the state of New York. Exception: New York State. Names of states, territories and possessions of the United States should be spelled in full running text. For addresses on envelopes, use the two-letter state postal code (see table below) with zip code. There is no comma between the city name and postal code and zip code. Example:

  
  Office of Admissions
  San Diego State University
  5500 Campanile Drive
  San Diego CA 92182-7455
  

  Standard Abbreviations: Use standard abbreviations for state names. Alaska, Hawaii, Idaho, Iowa, Maine, Ohio, Texas and Utah are never abbreviated.

• T-shirt

• telephone numbers
  Use figures. Use hyphens, not periods: 212-555-1500, 555-1500 (not 555.1500). Do not use parentheses for the area code. For toll-free numbers, long-distance calls and in cases where it is required locally, use the prefix numeral 1: 1-800-555-1000. If extension numbers are given: ext. 2, ext. 364, ext. 4071. Use a comma to separate the main number from the extension. For international numbers, use the country code (in parentheses) and city or regional code (where required): (44) 20-7353-1515.

• temperature
  

  Do not use plus signs, minus signs, or the degree symbol when expressing temperatures in nontechnical copy. Use scale designations (Fahrenheit, Celsius, Kelvin) when necessary to avoid confusion. Follow whichever example is appropriate to your context:

The temperature fell to minus 20.
The temperature reached 7 below zero.
The temperature was 20 degrees Celsius.
The temperature was 20 degrees C.
It was 98 degrees Fahrenheit.
It was 98 degrees F.

Fahrenheit, Celsius, and their abbreviations are capitalized; centigrade, sometimes used in place of Celsius, is not. When temperature and gravity are expressed in technical text and lists, use figures; use a degree sign; the name of the thermometer is usually abbreviated:

68ºF, 32º C, 15º C, minus 10º F.
C centigrade or Celsius
F Fahrenheit
K Kelvin

• time (See also centuries, decades, years.)
  Use figures except for noon and midnight. Never write 12 noon or 12 midnight as this is redundant. Use a colon only when separating hours from minutes: 3 p.m., 7:30 a.m. Never write 3:00 p.m. Always include a.m. or p.m. with the time (lowercase and use periods). Avoid using "o'clock" when referring to time.

• titles (See also Titles, Academic in "General Academic Usage.")
  • titles of books, plays, movies, songs, etc. (capitalization, italics, and quotation marks in titles of works)
    

Articles, prepositions, and coordinate conjunctions should be lowercase in titles unless they are the first or last words; lowercase the to in infinitives:


The Last of the Mohicans
A Rage to Live

In addition to published books, pamphlets, newspapers, and periodicals, the titles of long poems, plays, major musical works, paintings, records, compact discs, audio- and videocassettes, television programs, and movies are capitalized and set in italics:

a story in the Los Angeles Times
an article in Foreign Affairs
Harold Pinter's The Servant
the film Heavenly Creatures
the television program Six Feet Under
Don Giovanni by Mozart
El Greco's View of Toledo
Tom Jones by Fielding

Exception: musical titles identifying musical form and/or key are set accordingly:

Fantasy in C Minor
Hungarian Rhapsody no. 12
William Tell Overture
Emperor Concerto

Titles of articles, songs, short poems, and parts of books are capitalized and enclosed in quotation marks:

"Silent Night"
"The Raven"
Professor Thackeray's article is titled "Which Way Is Up?"

Commas and periods are set inside of quotation marks; question marks and semicolons, outside of quotation marks (unless they are part of the matter quoted):

His thesis, "Man and His World," was. . . .
Do you like the song "Frere Jacques"?

• titles, personal
  Jr., III, 3rd, IV (no comma: Harry Jones Jr. or Harry Jones III.)

• troublesome terms

  a/an: Use "a" before consonant sounds and "an" before vowel sounds:

  The Civil War was a historical event.
  Poland is now a NATO member.
  The job requires someone with an MBA.
  Phil Jones was nominated for an honorary degree.

  about/around: Use "about" when you mean approximately; "around" refers to location.

  affect/effect: "Affect" is almost always a verb that means "to influence or put on": "His decision will affect many people." "Effect" is almost always a noun that means "result": "The effect of his decision will be felt for years."

  a lot: No such word as "alot."
  
  all right: not "alright."
  
  allude/elude: If you are making an indirect reference to something, you "allude" to it. To "elude" means to escape or avoid detection.

  and/or: Try to avoid.
  
  alternately/alternatively: "Alternately" means one after the other, in time or space. "Alternatively" means one instead of the other.
  
  barbecue: Not barbeque or Bar-B-Q.

  beside/besides: Beside means "next to" or "at the side of." Besides means "in addition to."

  bi/semi: Bi means "two," and semi means "half."

bimonthly: every two months
semimonthly: twice a month

This distinction is more difficult when referring to years:

semiannual: twice a year
biennial: something that happens every two years

can/may: "Can" denotes ability, but "may" denotes possibility and permission.

compose/comprise: Something is "composed" of something else (meaning "made up"), but one thing "comprises" another (includes).

"The committee was composed of two teachers, one politician, and three students."
"His speech comprised five major themes."

continual/continuous: "Continual" means repeated or intermittent; "continuous" means unbroken.

differ from/differ with: Politicians "differ from" (are unlike) each other, but they may not "differ with" (disagree) each other.

disinterested/uninterested: A "disinterested" (impartial) observer may be "uninterested" (lack interest) in the situation.

each/either/neither: When used as subjects, these three pronouns always take singular verbs. When they are used as adjectives, the nouns they modify always take a singular verb.

farther/further: "Farther" expresses physical distance. ("She can hike farther than her two sisters.") "Further" refers to degree, time or quantity. ("The board will discuss the proposal further at another time.")

Fewer/less (See less/fewer.)

hopefully: This word means "with hope" and describes how someone feels: "Hopefully, he opened the mailbox looking for the check." The following usage is incorrect: "Hopefully, the check will arrive."

irregardless: Do not use this word. Instead, use "regardless," which means "without regard for" or "unmindful of."

in/into: These prepositions are not interchangeable. "In" denotes location or position, and "into" indicates motion.

in order to: Wordy. You can usually omit "in order." (He went to the store in order to buy food for dinner.)

input: Jargon except in reference to computers. Use "information" or "opinion" instead.

interface: Use in the context of computers; in a human context, use "communicate" or "talk."

lay/lie: "Lay" is a transitive verb and requires a direct object. "Lie" is an intransitive verb and never takes a direct object. "Before lying down (no direct object), she laid the book on the table." (Book is the direct object.)
Don't confuse lie and lay in the past tense. The past tense of "lie" is "lay" (lie, lay, lain, lying); the past tense of "lay" is "laid" (lay, laid, laid, laying).

less/fewer: When you refer to number of individual items, use "fewer." When you refer to quantity, amount or bulk, use "less": "At DataCorp, fewer than 10 employees make less than $30,000 a year."

more than/over: These words are not interchangeable. Do not use "over" unless you are referring to a spatial relationship. For figures and amounts, use "more than": "She estimated that more than 100 people attended the workshop."

nonprofit/not-for-profit: These are interchangeable terms.

people/persons: If you are referring to an individual, you are referring to a "person." If you are referring to more than one, you are referring to "people," not persons.

plus: Use only in adding units. Otherwise, use "in addition," "also" or "and."

proved/proven: "Proved" is the past participle of the verb prove. "Proven" is an adjective.

Cynthia has proved that she deserves the promotion.
The Ford Mustang is a proven success.

please: Don't overuse.

preventive/preventative: "Preventive" is preferable to "preventative." (The extra syllable is unnecessary.)

reason why: This usage is redundant. Use "reason" alone or omit entirely:

"The reason you did not get the job is you are not qualified."
"You did not get the job because you are not qualified."

set/sit: The verb "set" requires an object: "Please set your books on the desk."
"Sit" never takes an object: "Please sit down so class may begin."

since/because: These words are not synonymous. "Since" is best used when it denotes a period of time, and "because" gives a reason or cause.

than/then: "Than" is used as a conjunction of comparison; "then" is an adverb denoting time.

toward: Not "towards."

utilize: "Use" or "employ" are preferable. ("He used his contacts to find a job.")

who, which, that: "That" is used to restrict meaning, and "which" is used to elaborate on it. "Who" can be used for both when it refers to people or things endowed by the writer with human qualities.

"She has finished the homework that is due tomorrow."
"The homework, which is a history report, is due tomorrow."
"Professor Jenkins, who assigned the homework, has taught history for 25 years."

who's/whose: If you want the contraction, meaning "who is," use "who's": "Who's going to bring cookies tomorrow?" If you want to denote possession, use the possessive pronoun "whose": "Whose office are we meeting at tomorrow?"

• United States or U.S.
  Spell out when used as a noun: "Who will be the next president of the United States?" Use U.S. (no space) only as an adjective: "She converted her U.S. dollars to British sterling."
  

• upside down (adv.) upside-down (adj.) The gymnast turned upside down. The text is printed upside-down.

• up-to-date (Hyphenate.)

• versus:
  "Against" or "in contrast with." Should be spelled out in general text but may be abbreviated to "vs." in common expressions like "guns vs. butter." Use "v." only in legal cases (Milton v. Thompson).

• workforce, work-study, workers' compensation (not workmen's compensation), workplace
  

• years:
  (See also entries for "academic years," "centuries," "dates," "decades," "months" and "years".)