Choice Style Guide: Abbreviations

ABBREVIATIONS, ACRONYMS, AND INITIALISMS (Chicago, ch. 10)

Choice acknowledges the following:

c (copyright: c1982)
c. (circa: c. 1900)
cf. (Latin confer, compare)
ed. (edited; use “ed. by” in entries and in text cites following book title)
e.g. (Latin, exempla gratia, for example; comma should precede and follow this expression)
et al. (Latin, et alii/aliae/alia, and others; refers to persons)
etc. (Latin, et cetera, and others; refers to things)
EU
i.e. (Latin, id est, that is; comma should precede and follow this expression)
Jr., Sr. (no comma between distinguishing terms and a personal name.)
MA, MS (no periods needed)
p. for page, pp. for pages (e.g., p. 47, pp. 43–57)
PhD (no periods needed)
UK
UN
US
USSR
v. (versus; used only for legal cases)
viz. (Latin, videlicet, namely)
WW I
WW II

Never begin a sentence with an abbreviation (or symbol or number).

On first reference, a full name or term should precede (not follow) its acronym. The acronym should be enclosed within parentheses.


World Health Organization (WHO) maximum likelihood estimate (MLE)
weak law of large numbers (WLLN)
English Revised Version (ERV)
certified nurse midwife (CNM)
Congress of Racial Equality (CORE)


Acronyms (AWOL, NATO, UNESCO, ZIP, RAND Corporation) are all capitalized and do not contain periods. Those commonly used as words are lowercased (e.g., laser, scuba, snafu).

In general, abbreviations formed from initial letters exclude periods (e.g., US, UK, USSR, UN).
Some academic degrees exclude periods (PhD, MA); some include them (Litt. D).

Plurals of abbreviations that contain no periods and no lowercase letters are formed by adding s without an apostrophe (BTUs, IQs, YMCAs).

State-name abbreviations occurring both in the entry and in the body of the review follow the two-letter form used by the US Postal Service.

Tanakh (TaNaKh): The acronym derived from the names of the three parts of the Hebrew Scriptures (the “Old Testament”)—Torah, Nevi’im, and Ketuvim. Webster’s Third International Dictionary gives it as Tannic, a spelling far less commonly seen than Tanakh. Use Tanakh.

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