Possessive nouns, or who owns what

To make a noun show possession, an apostrophe is needed. There are two general rules that cover most situations. These rarely present difficulties for writers. Problems sometimes arise with the exceptions to those rules.

• To form the possessive of a singular noun, add an apostrophe and an s.

After a semester at college, Tom had a greater appreciation for his mother's cooking.

The exception to this rule occurs when the singular noun ends with an s or z. You may have noted that sometimes an apostrophe and an s are used after a singular noun ending with s or z and sometimes only an apostrophe is used. So how do you know which is correct? Pronounce the word aloud. If you add a syllable when you say the word in the possessive, then it is correct to use an apostrophe and an s. Otherwise, only use an apostrophe.

One of the the lioness's cubs wandered away from the pride.

Achilles' heel was the only place he could be wounded.

• To form the possessive of a plural noun that ends with an s, add only an apostrophe after the s. To form the possessive of a plural noun that does not end in s, add an apostrophe and an s.
  

The Stevensons' car is two years older than ours. [The car belongs to more than one person.]

The employees' uniforms were ruined in the flood. [The uniforms of all the employees, not just one.]

The children's toys were scattered across the carpet.


Note that the placement of the apostrophe can change the meaning in the sentence:

The nurse's schedule is on the bulletin board. [There is one nurse.]

The nurses' schedule is on the bulletin board. [There is more than one nurse.]


Those are the basic rules. There are additional rules for special cases. The first one may seem obvious, but the other two often cause problems for writers.

• To form the possessive of a compound noun (one comprised of more than one word, with or without hyphens), add an apostrophe and s or an apostrophe at the end of the compound.

Jarred is painting his mother-in-law's house.

Memorial Day's weather was unseasonably cool.

• To form the possessive when two or more nouns own the same item(s), use an apostrophe and an s or an apostrophe after the last noun only.

Sally and Francie's presentation impressed the Mrs. Porter. [The two prepared a single, group presentation.]

Matt and Andy's mom teaches computer science. [Both have the same mom; they are brothers.]

• To form the possessive when two or more nouns individually own the same type of item, use an apostrophe and an s or an apostrophe after each noun.

Sally's and Francie's history reports were two days late. [Each girl wrote her own separate report; both reports were two days late.]

Matt's and Andy's moms baked cupcakes for the bake sale. [Both Matt's mom and Andy's mom - they are not brothers - baked cupcakes.]

In Brief: There are no shortcuts. Learn the rules so that misplaced apostrophes don't cause confusion for your readers.