Basic rules for Acronyms and Abbreviations

Abbreviation

An abbreviation (from Latin brevis "short") is a shortened form of a word or phrase. Usually, but not always, it consists of a letter or group of letters taken from the word or phrase. For example, the word "abbreviation" can itself be represented by the abbreviation "abbr." or "abbrev."

• Beginning a sentence. Never begin a sentence with a lowercase abbreviation.
• Common abbreviations such as etc., e.g., and i.e. may be used only in parentheses. In the text write for example (e.g.); and so forth (etc.); that is (i.e.).
• Traditional forms. A number of traditional honorifics and initials continue to be used, such as Mr., Mrs., Ms., Dr., A.M., Inc., Ltd., and J. S. Bach, E. E. Cummings, C. S. Lewis
• Use periods when making an abbreviation within a reference (Vol. 3, p. 6, pp. 121-125, 2nd ed.)

Acronym

Acronyms and initialisms are abbreviations, which are formed using the initial letters of words or word parts in a phrase or name.

• A term must be fully written the first time it is used, thereafter just the acronym is used.
• Explain what an acronym means the first time it occurs: American Psychological Association (APA).

• If an acronym is commonly used as a word, it does not require explanation (IQ, LSD, FBI, ESP).
• To form plurals of abbreviations, add s alone, without apostrophe (PhDs, IQs, vols., Eds).
• Use two-letter postal codes for U.S. states and Canadian provinces in references only (GA, PQ, etc.).