The Grammarphobia Blog


Q: This one has puzzled me for some time. In various publications, some acronyms are printed in all caps (NATO), while others are upper and lowercase (Nasdaq). I presume this is a stylistic choice rather than adherence to a hard-and-fast rule. Personally, I prefer CAPS as a clear signal that the word is an acronym.

A: Thanks for your question. I liked the subject line, and used it as the title of this item.

An acronym, as you know, is a kind of abbreviation. It’s made of the first letter (or letters) of the words in a phrase. Examples: “WAC,” for Women’s Army Corps, or “radar,” for radio detection and ranging.

An acronym, according to most definitions, is spoken as a word, unlike an initialism, such as “FBI” or “PTA.” I wrote about acronyms once before on the blog.

Capitalization is complicated when an acronym is a proper name. There are no hard-and-fast rules, and different publications have widely different styles.

The New York Times’s practice is to print acronyms of proper names entirely in capitals if they have four letters or fewer: NATO, NASA, PIN, SALT. With longer acronyms, only the first letter is capitalized: Unesco, Nascar, Unicef, Nasdaq, and so on.

The spell-checker in my email software, however, wants to cap all the letters of all the acronyms above (except for a couple that it doesn’t recognize).

When an acronym is a common noun, like “radar,” “laser,” or “scuba,” it’s generally treated like any other common noun, with all lowercase letters unless it’s at the beginning of a sentence or part of a title.

But there are exceptions even here. AWOL, for instance, is usually capped, though it’s sometimes seen with all lowercase letters.

Now, it’s time for me to go AWOL and take my two Labs for a walk.

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