10 Tips for Using Abbreviations Correctly

Guidelines for Using Abbreviations in Formal Writing

FAQ is an initialism for frequently asked questions. (Don Bayley/Getty Images)
Provided they are not obscure to the reader, abbreviations communicate more with fewer letters. Writers have only to ensure that the abbreviations they use are too well known to need any introduction, or that they are introduced and explained on their first appearance.
(Pam Peters, The Cambridge Guide to English Usage. Cambridge University Press, 2004)

Despite what you may have heard in school, abbreviations, acronyms, and initialisms are commonly used in formal writing (though more often in business and the sciences than in the humanities). Exactly how they should be used depends on your audience, the country you're living in (British and American conventions differ), and the particular style guide you're following.

Guidelines to Consider

  1. Using Indefinite Articles Before Abbreviations, Acronyms, and Initialisms
    The choice between a and an is determined by the sound of the first letter in the abbreviation: a before a consonant sound (a CBC documentary; a U.S. [or US] official) and an before a vowel sound (an ABC documentary; an MRI).
  2. Placing a Period at the End of an Abbreviation
    In American usage, an abbreviation that includes the first and last letters of a single word (Doctor, for example) is usually followed by a period (Dr.). In British usage, the period (or full stop) is usually omitted (Dr).
  3. Abbreviating the Titles of Doctors
    For medical doctors, write either Dr. Jan Jones or Jan Jones, M.D. (Don't write Dr. Jan Jones, M.D.) For nonmedical doctors, write Dr. Sam Smith or Sam Smith, Ph.D. (Don't write Dr. Sam Smith, Ph.D.)
  4. Abbreviating Months and Days
    If the month is preceded or followed by a numeral (14 Aug. or Aug. 14), abbreviate Jan., Feb., Mar., Apr., Aug., Sep. (or Sept.), Oct., Nov., Dec. Don't abbreviate May, June, and July. As a general rule, don't abbreviate the month if it appears alone or with just the year. And don't abbreviate the days of the week unless they appear in charts, tables, or slides.
  1. Using Common Abbreviations
    Certain abbreviations are never spelled out: a.m., p.m., B.C. (or B.C.E.), A.D. (or C.E.). Unless your style guide says otherwise, use lower case or small capitals for a.m. and p.m. Use capital letters or small caps for B.C. and A.D. (the periods are optional). Traditionally, B.C. comes after the year and A.D. comes before it, but nowadays the abbreviation commonly follows the year in both instances.
  2. Using the Abbreviation Etc.
    The Latin abbreviation etc. (short for et cetera) means "and others." Never write "and etc." And don't use etc. at the end of a list introduced by "such as" or "including."
  3. Placing a Period After Each Letter in an Acronym or an Initialism
    Though there are exceptions, as a general rule omit the periods: NATO, DVD, IBM.
  4. Punctuating an Abbreviation at the End of a Sentence 
    Use just one period when an abbreviation appears at the end of a sentence. The single period does double duty—marking the abbreviation and closing the sentence.
  5. Avoiding RAS Syndrome
    RAS syndrome is a humorous initialism for "Redundant Acronym [or Abbreviation] Syndrome syndrome." Avoid redundant expressions such as ATM machine and BBC corporation.
  1. Avoiding Alphabet Soup
    Alphabet soup (also called initialese) is a metaphor for an overabundance of abbreviations and acronyms. If you're unsure whether the meaning of an abbreviation is familiar to your readers, write out the word.