Using Apostrophes

The apostrophe has two primary uses: to form possessives of nouns and to show the omission of letters (forming contractions). It is also used to indicate certain plurals of lowercase letters. Apostrophes are NOT used for possessive pronouns or for noun plurals, including acronyms.

Forming possessives of nouns

How do you determine if a noun should be made possessive? Creating a phrase with “of” will tell you.

            a dollar’s worth = the worth of a dollar               Albert’s friend = a friend of Albert

 

Note: A common ungrammatical phrasing involving names, like the second example, is “a friend of Albert’s”; this is incorrect.  A noun must follow the “of,” so the logical question would be, “A friend of Albert’s what?”

If the noun after “of” is a building, an object, or a piece of furniture, no apostrophe is needed.

room of the hotel = hotel room                            door of the car = car door
leg of the chair = chair leg                                  frame of the picture = picture frame

When you know whether you need to make a noun possessive, follow these rules:

Add an apostrophe followed by an s to the singular form of the noun:

 

            the teacher’s desk                                             James’s desk

            the class’s subject                                             one student’s paper

Add an apostrophe followed by an s to plural nouns that do not end in s:

            the children’s toys                                             the women’s softball game

            the people’s choice                                            the geese’s migration

Add an apostrophe to the end of plural nouns that end in s:

            the teachers’ desks                                            two students’ papers

            the classes’ subjects                                          the swans’ migration

 

A simple trick to remember is that whenever you make a noun possessive, add an apostrophe to the end of the word. Then, if you pronounce an added s sound, add an s—if you do not add an s sound, do not add an s.

           

            one cat; one cat’s kittens                                   two cats; two cats’ kittens

            one boss; one boss’s office                                two bosses; two bosses’ offices

 

Add an apostrophe followed by an s to the end of compound words:

 

            my father-in-law’s recipe                                   The notary public’s seal

 

Note: Compound words are made plural after the most important word—usually the one functioning as the noun, not the adjective.  So the plural of “father-in-law” is “fathers-in-law,” and the plural possessive would be “fathers-in-law’s” if you were talking about what more than one father-in-law possessed.

Add an apostrophe followed by an s to the last noun to show joint possession of an object:

            Michael and Judy’s car                                      Laura and Ann’s house                         

Showing the omission of letters and numbers

Apostrophes are used in contractions. A contraction is a word or set of numbers in which one or more letters or numbers have been omitted. The apostrophe shows this omission. To use an apostrophe to create a contraction, place an apostrophe where the omitted letter(s) would go. Here are some examples:

            don’t = do not                            you’re = you are                        they’re = they are                      it’s = it is                                  

            who’s =       who is                          wouldn’t = would not                 can’t = cannot                           could’ve = could have                   

            the '90s = the 1990s

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Forming plurals of lowercase letters

Apostrophes are used to form plurals of letters that appear in lowercase, like “five qs” versus “five q’s” to make it clearer that the s is separated from the letter and is added to form a plural, not part of a word or an abbreviation. To form the plural of a lowercase letter, add an apostrophe and an s after the letter. There is no need for apostrophes indicating a plural on capitalized letters, numbers, and symbols.

            You should mind your p’s and q’s.

            The Art Department has several Macintosh G5s.

Note: Style guides such as those on MLA format used to suggest adding an apostrophe and an s to pluralize capitalized letters, numbers, and symbols, and some editors and professors still prefer them, so it is a good idea to ask.

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Common Apostrophe Errors to Avoid
 

Mixing up it’s and its
 

Wrong: Every vacation has it’s own ups and downs
Right: Every vacation has its own ups and downs
 

Pluralizing words with apostrophes
 

Wrong: “Hem’s Mended and Alteration’s Made.”
Right: “Hems Mended and Alterations Made.”
 

Using improper contractions
 

            Wrong: Your going to have to revise your essay.
            Right: You’re going to have to revise your essay.

Pluralizing names with apostrophes
 

            Wrong: We visited the Jones’s.
            Right:  We visited the Joneses.
 

Note: You could, however, say that you dropped by the Jones’s house, since in this case, the house is owned by the Joneses, so the word should be made possessive in front of “house.”