TIP Sheet
THE APOSTROPHE

 

The apostrophe is used to replace missing letters in contractions, to indicate the possessive form of certain nouns, and to form the plural of some words in very specific situations.

1. Use an apostrophe in a contraction to indicate missing letters in words or missing numbers in a year.

can't (can not)	he'd (he would)
I'm (I am)	it's (it is or it has)
you're (you are)	'99 (1999)
haven't (have not)	'03 (2003)
there's (there is)	o'clock (of the clock)

2. Use an apostrophe in the possessive form of a noun to indicate ownership. To show
ownership, add apostrophe + s to the end of a word, with one exception: To show ownership with a plural noun already ending in s add only the apostrophe.

• All singular nouns show possession by adding apostrophe + s ('s), including those that already end in s.

A boy's shirt is under the chair.
The child's toy was on the shelf.
Lois's book is fascinating.
The bus's door was still open.

• To show possession for a plural noun that does not end in s, add an apostrophe + s ('s).

The men's hats were purchased at our store.
She wanted to be the people's princess.

• To show possession for a plural noun that already ends in s, add only an apostrophe (').

The boys' uniforms were in the locker room.
She found the birds' nests under the tree.

3. Avoid common mistakes using the apostrophe.

• Do not use an apostrophe with possessive pronouns that end in s. Possessive pronouns are already possessive by definition and therefore do not require an apostrophe:

its

his

hers

ours

yours

theirs

whose

 

• Do not use an apostrophe when adding s to the end of a noun simply to make it plural.

 

The fruit stands were selling apples, pears, and walnuts.

• The word it's (with an apostrophe) is a contraction and should be used only in place of it is or it has. The word its (with no apostrophe) is a possessive pronoun and therefore never takes an apostrophe.

 

I'm sure you realize it's a holiday. (It's is a contraction for it is.)
It's been such a long time. (It's is a contraction for it has.)
The house lost its roof in the storm. (The possessive pronoun its already indicates
ownership by definition and therefore needs no apostrophe.)

The word you're is a contraction and should be used only in place of you are. The word your is a possessive pronoun and never takes an apostrophe.

I presume you're planning to bring your coat on the hike. (I presume you are planning to bring the coat that belongs to you on the hike.)

 

• The word who's is a contraction and should be used only in place of who is or who has.
  The word whose is a possessive pronoun and never takes an apostrophe.

Who's on first? (Who's is a contraction for who is.)
Who's been turning off the lights? (Who's is a contraction for who has.)
Whose book is on the table? (Whose is a possessive pronoun that already indicates ownership by definition and therefore needs no apostrophe.)

4. Additional rules apply to the use of apostrophes in certain specific situations.

• Some sources state that an apostrophe + s should be used to indicate plural forms of words used as words, numbers, letters, and abbreviations.

maybe's

8's

I.D.'s

A's and B's

However, MLA format differs somewhat by recommending no apostrophe for the plural form of numbers and abbreviations.

1980s

VCRs

the ‘70s

7s and 8s

• If a noun is compound, use the apostrophe and s with the last element only.

Her brother-in-law's car was an antique.

• To indicate joint ownership, add the apostrophe and s to the last noun only. To indicate
  separate ownership for more than one person, add the apostrophe and s to each noun.

Maria and John's wedding lasted all day.
Maria's and John's expectations of marriage were very different.