Guidelines for Using Abbreviations in Formal Writing

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. —From The Cambridge Guide to English Usage by Pam Peters Despite what you may have heard in school, abbreviations, acronyms, and initialisms are commonly used in formal writing (though youll find them more frequently in business and the sciences than in the humanities). Exactly how they should be used depends on your audience, the country youre living in (British and American conventions differ), and the particular style guide youre following. 10 Tips for Using Abbreviations Correctly 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. Use a before a consonant sound (for example, a CBC documentary or a U.S. official). Use an before a vowel sound (an ABC documentary or an MRI).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.), while In British usage, the period (or full stop) is usually omitted (Dr).Abbreviating the Titles of Doctors: For medical doctors, write either Dr. Jan Jones or Jan Jones, M.D. (Dont write Dr. Jan Jones, M.D.) For nonmedical doctors, write Dr. Sam Smith or Sam Smith, Ph.D. (Dont write Dr. Sam Smith, Ph.D.)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 o r 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.Abbreviating Months and Days: If the month is preceded or followed by a numeral (14 Aug. or Aug. 14), abbreviate months as follows: Jan., Feb., Mar., Apr., Aug., Sep. (or Sept.), Oct., Nov., Dec. Dont abbreviate May, June, or July. As a general rule, dont abbreviate the month if it appears alone or with just the year—and dont abbreviate the days of the week unless they appear in charts, tables, or slides.Using the Abbreviation Etc.: The Latin abbreviation etc. (short for et cetera) means and others. Never write and etc. Do not use etc. at the end of a list introduced by such as or including.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.Punctuating an Abbreviation at the End of a Sentence: Use a single period when an abbreviation appears at the end of a sentence. The single period does double duty—marking the abbreviation and closing the sentence.Avoid 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.Avoid Alphabet Soup: Alphabet soup (a.k.a. initialese) is a metaphor for using an overabundance of abbreviations and acronyms. If youre unsure whether the meaning of an abbreviation is familiar to your readers, write out the entire word.