Apostrophe: Special cases

An apostrophe typically is not used to pluralize numbers, letters, abbreviations, and words mentioned as words.

Different disciplines have different conventions for using or omitting apostrophes. Check the style guide for the discipline in which you are writing, and be consistent throughout your paper.

No apostrophe with plural numbers

Omit the apostrophe in the plural of all numbers, including decades.

Example sentence: Oksana skated nearly perfect figure 8s.

Example sentence: The 1920s are known as the Jazz Age.

Apostrophe with plural letters

Use of an apostrophe is usually optional for a plural letter. Italicize the letter and use regular font style for the -s ending. Do not italicize academic grades.

Example sentence: Two large Js [or J's] were painted on the door.

MLA NOTE:The Modern Language Association recommends the apostrophe for the plural of both capital and lowercase letters.

No apostrophe with plural abbreviations

Do not use an apostrophe to pluralize an abbreviation.

Example sentence: We collected only four IOUs out of forty.

Example sentence: Marco earned two PhDs before his thirtieth birthday.

Apostrophe with plural of words mentioned as words

Generally, omit the apostrophe to form the plural of words mentioned as words. If the word is italicized, the -s ending appears in regular font style.

Example sentence: We've heard enough maybes.

Words mentioned as words may also appear in quotation marks. When you choose this option, use the apostrophe.

Example sentence: We've heard enough “maybe's.”

Apostrophe with potentially confusing spellings

The apostrophe is sometimes used for spellings that would otherwise present a confusing appearance.

Although the plural of most capital letters and most numbers are not misread without an apostrophe, some plurals (As, Is, and 0s, for example) can be misread without the apostrophe.

Example sentence: The Oakland A's won three consecutive World Series in the early 1970s.

Example sentence: Binary code is a series of 0's and 1's.

Exercises:

The apostrophe 1

The apostrophe 2