Do Acronyms Need Periods?

Is it FBI or F.B.I.? PhD or Ph.D.? And once we solve the question about periods or no periods, we still have spaces and capitalization to contend with. Let’s talk acronyms!

What Is an Acronym?

An acronym is a word that is formed from the first letter or letters of each word in a compound phrase.

Technically speaking, you must be able to pronounce an acronym as a word (like “NATO” and “laser”). If you pronounce each of the letters individually (like “FBI” and “TBA”), it’s an initialism. In this post, we’re talking about the formatting of both acronyms and initialisms.

Periods or No Periods?

According to The Copyeditor’s Handbook, “all the major style manuals recommend that acronyms be set in uppercase letters with no internal periods.”

This rule—all uppercase, no periods—holds up! The Chicago Manual of Style agrees that abbreviations that include two or more capital letters should have no periods, but the manual does mention a couple of caveats:

• Use no periods with abbreviations that include two or more capital letters, even if the abbreviation also includes lowercase letters: VP, CEO, MA, MD, PhD, UK, US, NY
• Use periods for initials standing for given names: E. B. White; do not use periods for an entire name replaced by initials: JFK
• Use periods with abbreviations that end in a lowercase letter: p. (page), vol., e.g., i.e., etc. a.k.a., a.m., p.m., Ms., et al.

In short, acronyms and initialisms should be spelled with no periods. The only exceptions to this rule are those few acronyms that use only lowercase letters (like a.m., p.m., e.g., and i.e.) and peoples’ names (as in M. Johansson). Abbreviations like p. for page, vol. for volume, Mr., and Ms. are not acronyms or initialisms, and they do require periods at the end.

Capitalization

Acronyms and initialisms are generally set in all uppercase letters (NFL, NAACP, OMG).

Some newspapers have started a new trend, however, that could catch on in the corporate and book publishing worlds: They’re using full capital letters for all initialisms, full capital letters for acronyms that are three or four letters long, but initial capital letters only for acronyms that are five letters or longer. So NAACP and TBA would be all caps (initialisms), NATO and GIF would be all caps (shorter acronyms), but Nafta and Captcha would be initial caps only (longer acronyms).

Some of those longer acronyms start to become lowercase as people use them more and more often. For example, words like laser, scuba, and radar are all acronyms that started out all caps but gradually became so familiar that we went ahead and lowercased them.

So the safe bet is to use all capital letters for acronyms and initialisms, but you can check the Merriam-Webster dictionary for those longer acronyms to see if it’s become standard to lowercase them!

The spelled-out version of acronyms and initialisms is a different story, however. When you’re defining an acronym, you should only capitalize the proper nouns and adjectives.

Please read the list of FAQs (Frequently Asked Questions) before visiting. —not a proper noun

Please read the list of FAQs (frequently asked questions) before visiting.

The FBI (Federal Bureau of Investigation) is looking into this case.

The FBI (federal bureau of investigation) is looking into this case. —proper noun

Even though the first letters of each word are capitalized in the acronym, they should not be capitalized when spelled out unless they are proper nouns or adjectives.

What About Spaces?

For initialisms and acronyms, which have no internal periods, there should be no space between the letters.

NASA

N.A.S.A.

N. A. S. A.

N A S A

When you’re just abbreviating a couple of words (not an acronym or initialism), you should leave space between the abbreviated words, as in Gov. Gen. or Dist. Atty.

When there is an ampersand used within an initialism, you should not leave any space on either side of it.

Texas A&M

Texas A & M

R&D

R & D

Q&A

Q & A

One More Style Rule for Acronyms

Acronyms and initialisms should only be italicized if the word would be italicized when spelled out.

Please reference the OED (Oxford English Dictionary).

Please reference the OED (Oxford English Dictionary).

Book names are italicized, so the abbreviated form of the book name should also be italicized.

I saw the news on CNN.

I saw the news on CNN.

“Cable News Network” would not be italicized when spelled out, so the abbreviation also does not need to be italicized.

What questions do you have about styling acronyms? Let me know in the comments, and I’ll find an answer for you!

Click here to see 17 words you never knew were acronyms!

Sources:

• The Chicago Manual of Style. 17th ed. Chicago, IL: The University of Chicago Press, 2017.
• Ebbitt, D. R., and W. R. Ebbitt. Index to English. 8th ed. New York: Oxford University Press, 1990.
• Einsohn, Amy. The Copyeditor’s Handbook. 3rd ed. Berkeley and Los Angeles, California: Univ of California Pr, 2011.