A workshop participant asked me the following:

1. 5 Cs or 5 C’s of credit–which one is correct?
2. What is the plural form of Contract to Sell? Plural form of its acronym, CTS?

First off, let me explain the difference between an acronym and an initialism.

An initialism is made up of initial letters of words, and each letter is pronounced separately (sometimes an initialism has periods; sometimes it doesn’t). Examples: p.m., DOJ, FEU, U.S.

An acronym is an initialism that has become a word in its own right, and is pronounced as a word rather than as a series of letters. Examples: scuba, laser, DoTA, AIDS, SARS. The word scuba, for instance, means self-contained underwater breathing apparatus. The word laser means light amplification by stimulated emission of radiation.

Now, let’s make plurals! :)

1. It’s 5 C’s of credit–with the apostrophe. Usually, we don’t add the apostrophe to create plurals, but we do so for single letters (e.g., The 5 C’s of Credit Transactions or ). Why? Because without the apostrophe, the term (that is, 5 Cs of credit) will look awkward and hard to read. Example: mind your p’s and q’s.

To make plurals of acronyms and initialisms, just add the small letter. No need to add the apostrophe (let’s reserve the apostrophe for possessives).


the 1990s
the DVDs
the ROIs
the CEOs


  • When there is only one letter. So we say something like The Three M’s of Marriage.
  • When the acronym or initialism ends with S. When the acronym or initialism ends with S, adding only the small letter s makes the term look awkward. It’s OK to add the apostrophe in this case. For example, the CTS’s.
  • When the acronym or initialism ends with periods. Same reason–not including the apostrophe makes the term look awkward. So we say, B.A.’s and A.A.’s.

2. Note, however, that when we use the full term–instead of the acronym or initialism–the plural is Contracts to Sell because the relevant word is the noun contracts and the phrase to sell is merely a description (we do not make plurals of descriptions/adjectives). Remember that the subject is not in a prepositional phrase because a prepositional phrase functions as an adjective (descriptive). This means that when we create the plural of a compound term that contains a prepositional phrase, we do not change the prepositional phrase. Adjectives have no plural inflections.

In a compound term, what we make plural is the relevant noun. Therefore, we have:

editors-in-chief (here, the main noun is editor, not chief)
training assistants (here, the main noun is assistants; the word training is merely an adjective/description)
chiefs of staff (the prepositional phrase of staff is only an adjective)
officers in charge
commanders in chief

Thus, the plurals of land titles are:

a. Transfer Certificates of Title (The word transfer and of title are only descriptions)
b. The plural of the initialism is TCTs.
c. What if we list many TCTs? The full term is Transfer Certificates of Title No. 13678, 294830 and 920473. Note that we do not add an s to No. because this term is only a description.
Capital Community College has the following discussion on plurals:

We use an apostrophe to create plural forms in two limited situations: for pluralized letters of the alphabet and when we are trying to create the plural form of a word that refers to the word itself. Here we also should italicize this “word as word,” but not the ‘s ending that belongs to it. Do not use the apostrophe+s to create the plural of acronyms (pronounceable abbreviations such as laser and IRA and URL*) and other abbreviations. (A possible exception to this last rule is an acronym that ends in “S”: “We filed four NOS’s in that folder.”)

Jeffrey got four A’s on his last report card.
Towanda learned very quickly to mind her p’s and q’s.
You have fifteen and’s in that last paragraph.

Photo credit: The Voice of a Translator


One thought on “Plurals of Acronyms

  1. Pingback: Dos and don’ts | Using a Borrowed Language

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