24. Apostrophes

See C2 in the Quick Editing Guide for advice on editing for apostrophes.

Use apostrophes for three purposes: to show possession, to indicate an omission, and to add an ending to a number, a letter, or an abbreviation.

24a To make a singular noun possessive, add -’s

The plumber’s wrench left grease stains on Harry’s shirt.

Add -’s even when your singular noun ends with the sound of s.

Felix’s roommate enjoys reading Henry James’s novels.

Possessive Nouns and Plural Nouns at a Glance

Both plural nouns and possessive nouns often end with -s.

  • Plural means more than one (two dogs, six friends), but possessive means ownership (the dogs’ biscuits, my friends’ cars).
  • If you can substitute the word of for the -s’ (the biscuits of the dogs, the cars of my friends), you need the plural possessive with an apostrophe after the -s.
  • If you cannot substitute of, you need the simple plural with no apostrophe (the dogs are well fed, my friends have no money for gas).

Some writers find it awkward to add -’s to nouns that already end in an -s, especially those of two syllables or more. You may, if you wish, form such a possessive by adding only an apostrophe.

The Egyptian king Cheops’ death occurred centuries before Socrates’.

24b To make a plural noun ending in -s possessive, add an apostrophe

A stockbrokers’ meeting combines foxes’ cunning with the noisy chaos of a boys’ locker room.

24c To make a plural noun not ending in -s possessive, add -’s.

Nouns such as men, mice, geese, and alumni form the possessive case the same way as singular nouns: with -’s.

What effect has the women’s movement had on children’s literature?

24d To show joint possession by two people or groups, add an apostrophe or -’s to the second noun of the pair

I left my mother and father’s home with friends and neighbors’ good wishes.

If the two members of a noun pair possess a set of things individually, add an apostrophe or -’s to each noun.

Men’s and women’s marathon records are improving steadily.

24e To make a compound noun possessive, add an apostrophe or -’s to the last word in the compound

A compound noun consists of more than one word (commander in chief, sons-in-law); it may be either singular or plural.

The commander in chief’s duties will end on July 1.

Esther does not approve of her sons-in-law’s professions.

24f To make an indefinite pronoun possessive, add -’s

Indefinite pronouns such as anyone, nobody, and another are usually singular; they form the possessive case with -’s. (See 24a.)

What caused the accident is anybody’s guess, but it was no one’s fault.

24g To indicate the possessive of a personal pronoun, use its possessive case

personal pronoun: A pronoun (I, me, you, it, he, we, them) that stands for a noun that names a person or thing: Mark awoke slowly, but suddenly he bolted from the bed.

The personal pronouns are irregular; each has its own possessive form, none with an apostrophe. Resist adding an apostrophe or -’s.

NOTE:Its (no apostrophe) is always a possessive pronoun.

I retreated when the Murphys’ German shepherd bared its fangs.

It’s (with an apostrophe) is always a contraction of it is.

It’s [It is] not our fault.

24h Use an apostrophe to indicate an omission in a contraction

See C2 in the Quick Editing Guide for a chart of possessive personal pronouns.

They’re [They are] too sophisticated for me.

Pat didn’t [did not] finish her assignment.

Americans grow up admiring the Spirit of ’76 [1776].

It’s [It is] nearly eight o’clock [of the clock].

24i Use an apostrophe to form the plural of a letter or word mentioned as a word

See advice on italicizing a letter, word, or number named as a word.

LETTER How many n’s are there in Cincinnati?
WORD Try replacing all the should’s in that list with could’s.

No apostrophes are needed for plural numbers and most abbreviations.

DECADE The 1990s differed greatly from the 1980s.
NUMBER Cut out two 3s to sew on Larry’s shirt.
ABBREVIATION Do we need IDs at YMCAs in other towns?