Initialisms and Acronyms

By Mark Nichol

Most people know what an acronym is. But few are as familiar with term initialism, or of an important distinction between the two.

An acronym is an initial abbreviation that can be pronounced as a word, such as NASA or WASP. This term is also used to refer to a series of initials pronounced individually, such as FBI or TGIF, but the technical term is initialism. What’s the BFD (“big, fat deal,” though another word starting with f is sometimes used)? The answer is the.

Because acronyms like NASA are pronounced as words (“na-suh,” in this case), there’s no need to precede them with the definite article: You wouldn’t write “Budget cutbacks hit the NASA hard.” (Though the is essential if NASA is used as an adjective, as in “Budget cutbacks hit the NASA project hard.”)

But initialisms require the: “The FBI announced his capture several hours later.” That’s because the term is pronounced letter by letter: “eff-bee-eye.” (The only usage that omits the definite article is in a headline: “FBI Announces Suspect’s Capture.”)

And when do you use an acronym or an initialism, when do you spell it out, and when do you do both? In more formal writing, the standard approach is to introduce an agency, organization, or some other entity that uses such an abbreviation, or abbreviations of terminology, by spelling out the name on first reference.

If a subsequent reference (called, in publishing, the second reference, no matter how many times it is repeated) appears in proximity — say, the same paragraph — and few, if any, other abbreviations appear in the interim, simply use the abbreviation thereafter.

However, if the next usage is farther away, it’s best to insert the abbreviation in parentheses immediately after the spelled-out reference to establish an association in the reader’s mind when it’s not supported by proximal use of the abbreviation. If the abbreviation is not mentioned again for some time, or it appears only up to a handful of times, spelling it out again (perhaps every time) is a good idea. Depending on the term and the publication, however, the hand-holding parenthesis may be unnecessary.

Many specialized publishers maintain a list of abbreviations familiar to readers of their publications that specifies whether each one requires abbreviation accompanying the spelled-out first reference, or needs to be spelled out at all.

For example, an astronomy magazine is likely to note in its house style guide that NASA does not need to be spelled out, and many other publications do likewise because of the familiarity of the agency’s name in our society. By contrast, less common abbreviations like OEM (original equipment manufacturer) should be spelled out except in a manufacturing-industry publication. As with many usage prescriptions, it’s all about the context.

Oh, and one more point, so to speak: Notice that no acronym or initialism is this post includes periods. They’re generally considered outdated and superfluous. Even two-letter forms like AM and PM, MD and RN, and BC and AD go without, though US stubbornly retains them in many publications.

41 Responses to “Initialisms and Acronyms”

  • M Leybra

    Mimi, how about in writing, follow the vowel rule, w/ ‘an’ preceding words beginning w/ a vowel, a,e,i,o,u, but ‘a’ preceding ‘F’ as in FBI, regardless of “aligning it w/ how FBI might be said out loud.” I disagree w/ Mark Nichol on this as well as writing U.S. as US. This short-shrift recently introduced, started w/ newer generation of newspaper article writers, under-educated in grammar & the influence of computer language, not to mention a whole generation of text messaging users who likely don’t place much importance on the study of grammar anymore unless they’re course of study will require it. Plus the world is overflowing today w/ initialisms & acronyms as never before. As well, the school system in this country is no longer what it once was when teachers took responsibility & personal pride in how well ‘their’ students were educated.

  • Nick

    SQL is an initialism (structured query language) usually pronounced as sequel. Not sure what that makes it!

  • Genia Garibaldi

    Good discussion here about acronyms and initialisms. I stumbled on this site while looking for some guidance about whether it is acceptable to begin a sentence with an intialism. It is my understanding that it is okay to begin a sentence with an acronym. I’ll appreciate any enlightenment provided.

  • Noah

    I think the article is wrong about initialism. I know that you need the definite article in front of “FBI” but that is not true for all cases. For example: UCLA. You never use an article in front of UCLA. You always say I went to UCLA, not the UCLA.

  • Pam Strickland

    The Associated Press style does not abbreviate Texas. It is simply Texas, not Tex.

  • Mark Nichol


    As with many other aspects of postsecondary education, what is common practice is not necessary commonsensical. I will give a big virtual hug to anyone who can explain why we don’t precede initialisms of institutions of higher educations (or expressions like “U. of M.” — for the University of Michigan, for example) with the

    As for referring to states, the style for most book and magazine publishers is to spell state names out — the most elegant solution, most assuredly. But many publications follow the lead of newspapers, which traditionally abbreviate and elide with abandon, to save space — and, in the days of hot type, effort.

  • Emma

    Cecily: Thanks for the clarification on “BBC”/”the BBC”.

    I also realized that the initialisms to refer to universities often are not preceded by “the” (again, at least in American usage). I wonder what the consistency with this is, since in most cases I believe the “the before initialism” rule would apply. Would it just be considered on a case-by-case basis?

    Mark: I honestly would prefer that publications use the longer abbreviation (such as “Mont.” for “Montana”) rather than the two-letter postal code because some of the codes seem like they could potentially refer to many different states and I don’t know all fifty of them by heart. I presume many other people are in the same boat.

  • Mark Nichol

    This just in:

    The newest edition of The Chicago Manual of Style, the most popular and respected guideline for word treatment, has caught up with common sense (something the otherwise excellent resource very occasionally fails to do):

    “In works following Chicago’s primary recommendation of using two-letter postal codes for states (e.g., MT, not Mont., for Montana), US rather than U.S. is now preferred.

  • Mark Nichol


    Some initialisms resist omission of periods, and often do so for good reason: In these cases, because the abbreviations are lowercase, ie and eg are, I think, too likely to be mistaken for typos.

  • HeatherB

    Are i.e. (id est) and e.g. (exempli gratia) changing as well?

  • Kathryn

    Sigh–what happens when you are thinking about two things at once. Now I’ve made myself look VERY stupid and ignorant–I meant “article” everywhere I used “pronoun” in that last post. *cringes*

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