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1.16 Acronyms and initialisms

An acronym is a pronounceable word formed from the first letters of a series of other words, such as NAFTA, NATO or GATT. An initialism is formed from the initial letters of a series of words and may not be pronounceable as a word. Examples are GST, RCMP, OECD and IDRC. The distinction is a fine one and is often overlooked in practice. Do not use periods or spacing between the letters of an acronym or initialism.

In general, acronyms are not preceded by the definite article:

  • The members of NATO rejected the idea.
  • NAFTA may be expanded to Chile and other South American countries.
  • CIDA provides grants, loans and lines of credit.

Usage varies with respect to initialisms. Those representing the names of organizations generally take the definite article, while those representing a substance, method or condition do not:

  • The CLRB is reviewing the case.
  • The unit has provided training in CPR for some time.

The correct form of the indefinite article (a or an) to use before acronyms and initialisms is determined by the consonant or vowel sound of the initial syllable, letter or number. The following examples illustrate correct English usage. Note that ease of pronunciation is the key:

  • a 3M product
  • a UFO sighting
  • an IMF loan
  • an ACTRA award
  • a QFL convention
  • a NAFTA-related issue
  • an NHL referee
  • an FM station

Use upper-case letters for acronyms or initialisms in their entirety, even if some of the component words or their parts are not normally capitalized—unless the organization concerned prefers lower case:

  • CAA
    • Canadian Automobile Association
    • Ontario Secondary School Teachers’ Federation
    • formula translation
    • Canada Institute for Scientific and Technical Information


Acronyms (not initialisms) of company names formed by using more than the initial letters of the words they represent. Usually, only the first letter of the acronym is capitalized:

  • Alcan
    • Aluminum Company of Canada
  • Inco
    • International Nickel Company
  • Nabisco
    • National Biscuit Company
  • Nortel
    • Northern Telecom Ltd.
  • Stelco
    • Steel Company of Canada Ltd.

Initialisms are always fully capitalized:

  • BBS
  • VIP
  • TSE
  • CNCP Telecommunications
  • HRDC2

Common-noun acronyms treated as fullfledged words, such as radar, laser, scuba and snafu, are written entirely in lower case without periods.

When using acronyms or initialisms such as SIN (social insurance number), PIN (personal identification number) or ISBN (International Standard Book Number) do not repeat the word number (e.g. "SIN number"). Either write the expression out in full or use the abbreviated form on its own.


  • Back to the note2 For a comprehensive list of the official acronyms and initialisms of Canadian government organizations, consult the Treasury Board’s Federal Identity Program Manual, "Titles of Federal Organizations."