Posted by: Jack Henry | May 1, 2017

Editor’s Corner: Using Periods in Acronyms and Initialisms

Do you have trouble remembering whether to include periods in abbreviations like ATM, NASA, and TGIF (or A.T.M., N.A.S.A., and T.G.I.F.)?

Good news! Our rule is much easier than you might think: Don’t use periods between each letter.

Acronyms vs. Initialisms

Much of the confusion comes from the fact that some abbreviations are pronounced as words (like NATO and UNICEF) and other abbreviations are pronounced as a series of letters (like FBI and CIA).

Many people use the word acronym to describe both types of abbreviations, but some sticklers distinguish between acronyms and initialisms.

The Oxford English Dictionary is very clear about this distinction:

· acronym: an abbreviation formed from the initial letters of other words and pronounced as a word (e.g., ASCII, NASA)

· initialism: an abbreviation consisting of initial letters pronounced separately (e.g., BBC)

Merriam-Webster (our dictionary of choice) is less decisive:

· acronym: a word formed from the initial letter or letters of each of the successive parts or major parts of a compound term

· initialism: an acronym formed from initial letters; especially one that is pronounced as separate letters considers the two words to be synonyms, defining acronym as “an initialism” and vice versa.

For our purposes, the distinction doesn’t matter; we treat acronyms and initialisms exactly the same.

Chicago Manual of Style

Some style guides have complicated rules for dealing with abbreviations, taking into account how the word is pronounced, how long it is, and whether any two letters come from the same word (like the T and the V in MTV).

We follow The Chicago Manual of Style, which is clear on this point: “Use no periods with abbreviations that appear in full capitals.”

Ben Ritter | Technical Editor | Symitar®
8985 Balboa Avenue | San Diego, CA 92123
619-682-3391 | or ext. 763391 |

Symitar Documentation Services

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  1. […] my last post, I wrote about using periods in acronyms and initialisms (tip: don’t do it!). Today, just for fun, I’d like to talk about words that look like […]

  2. If I am reading this correctly, I do not need to use periods in FMLA, GED, and EMT in my novel, right? Also, I need to edit my manuscript before it goes to print! Thanks for the info!

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