A possessive noun is a noun that names who or what owns or has possession of something.
In most cases, for singular nouns to show that possession, we add an apostrophe and an a (‘s). For plural nouns we simply an apostrophe except for those few plural nouns that do not end in s.
With that said, this is an area of conflict and disagreement among writers and much of that disagreement stems from the requirements of particular styles.
There are different apostrophe rules for different styles. While this site is predominantly dedicated to AP style (the style for newspapers), in this section, differences between AP and and Chicago style are noted. In the following examples, those difference are noted.
When creating the possessive form of nouns, there are eight simple rules:
1. For both AP and Chicago style, if a singular noun does not end in s, add ‘s
- The delivery boy’s truck was blocking the driveway.
- Bob Dole’s concession speech was stoic and dignified.
NOTE: Even if the singular noun is a proper noun (i.e. a name) if it does not end in s, add ‘s.
- The student’s attempts to solve the problem were rewarded
2. If a singular common noun ends in s, Chicago and AP handle apostrophes differently. For both styles, if a singular common noun ends in s, add ‘s
FOR AP STYLE: if the word following the singular common noun ending in s begins with s, add an apostrophe only. (This includes words with s and sh sounds.)
- The boss’s temper was legendary among his employees. (AP and Chicago)
- The boss‘ sister was even meaner. (AP)
- The The boss‘s sister was even meaner. (Chicago)
- The witness’s version of the story has several inconsistencies. (AP and Chicago)
- The witness‘ story did not match the events recorded on tape. (AP)
- The witness’s story did not match the events recorded on tape. (Chicago)
3. If a singular proper noun (a name) ends in s, Chicago and AP handle apostrophes differently.
In AP style, if a proper noun ends in s or an s sound, add an apostrophe only.
- Chris‘ exam scores were higher than any other students.
In Chicago style, if a proper nouns ends in s add ‘s.
- Last year Kansas’s legislature passed a law.
EXCEPTION #1 IN CHICAGO STYLE: If a name is two or more syllables and ends in an eez sound, use only an apostrophe.
- The Ganges’ source is in the Himalayas.
EXCEPTION #2 IN CHICAGO STYLE: If the s at the end of the name is not pronounced, use only an apostrophe.
- Albert Camus’ novels are assigned in some classes.
EXCEPTION #3 IN CHICAGO STYLE: In “For . . . sake” expressions omit the s (following the apostrophe) when the noun ends in an s or an s sound.
- For goodness’ sake, apostrophe rules are confusing.
4. If a noun is plural in form and ends in an s, add an apostrophe only, even if the intended meaning of the word is singular (such as mathematics and measles.)
- The instructor asked us to analyze ten poems’ meanings.
- The dog catcher had to check all of the dogs’ tags.
- It is hard to endure the Marine Corps’ style of discipline.
5. If a plural noun does not end in s, add ‘s
- Many activists in Oregon are concerned with children’s rights.
- Everyone was disappointed with the American media’s coverage of the Olympics in Atlanta.
6. If there is joint possession, use the correct possessive for only the possessive closest to the noun.
- Clinton and Gore’s campaign was successful.
- She was worried about her mother and father’s marriage.
- Beavis and Butthead’s appeal is absolutely lost on me.
7. If there is a separate possession of the same noun, use the correct possessive form for each word.
- The owner’s and the boss’s excuses were equally false.
- The dog’s and the cats’ owners were in school when the fire broke out.
8. In a compound construction, use the correct possessive form for the word closest to the noun. Avoid possessives with compound
- My father-in-law’s BMW is really fun to drive.
- The forest ranger’s truck is painted an ugly shade of green.
- Your neighborhood letter carrier’s job is more difficult than you imagine.