The apostrophe is used to show possession and to form the plural of many nouns and symbols. (Possessive nou s and pronouns are also covered in Parts of Speech under Nouns and Pronouns.)
1) POSSESSIVE OF SINGULAR NOUNS
The possessive of a singular noun is formed by adding ( ‘s ). Names that end in a z sound often take only the apostrophe to avoid the awkwardness of too many s sounds.
Example:
- The mechanic’s wrench.
- The tree’s leaves.
- Moses’s tablets.
- Mrs. Gonzales’ maid.
- Gloria’s briefcase.
- Mr. Jones’ house.
- Gus’s workbench.
- Ned Stanis’s boots.
2) POSSESSIVE OF PLURAL NOUNS
The plural possessive of nouns ending in (s) is formed by adding only the apostrophe. All other plural nouns take ( ‘s ).
Example:
- The Harlands’ trip.
- Children’s shoes.
- The teams’ scores.
- The trees’ leaves.
- Men’s sports wear.
- Women’s networks.
3) INDEFINITE AND PERSONAL PRONOUNS
Indefinite pronouns (everyone, no one, anybody, everybody, someone, somebody, one) require an apostrophe to form the possessive. However, personal possessive pronouns (his, her, theirs, your/yours, my/mine, our/ours) do not use an apostrophe.
Example:
- Is this someone’s book?
- I’ll take anyone’s ideas.
- Yes, the book is hers.
- Your ideas are great.
4) INDIVIDUAL AND JOINT POSSESSION
When hyphenated words or names of organizations, companies, or individuals are used to show joint possession, only the last word takes ( ‘s ) or an apostrophe.
In cases of individual possession, both nouns or pronouns take ( ‘s ) or the apostrophe only.
Joint possession:
- Lin and Chan’s bicycles. (The bicycle is owned by both Lin and Chan.)
- The vice-presidents’ office. (The office is used by more than one vice president.)
- IBM and Xerox’s new venture. (The two companies are working together on one venture.)
Individual possession:
- Lin’s and Chan’s bicycles. (Notice the plural noun after the names—a clue that each person owns a bicycle.)
- Her father-in-law’s and brother’s golf scores.
- Texaco’s and Esso’s annual reports.
5) UNITS OF MEASURE AS POSSESSIVE ADJECTIVES
Units of measure such as day, week, yard, cent, and hour take an ( ‘s ) or an apostrophe when used as possessive adjectives.
Example:
- A moment’s peace.
- A month’s pay.
- A dollar’s worth.
- Ten minutes’ work.
- Three weeks’ pay.
- Two cents’ worth.
6) PLURAL FORMS OF SYMBOLS
The apostrophe or ( ‘s ) is used to form the plural of letters, numbers, signs, symbols, and words referred to as words.
Example:
- All the R’s in this article were printed backwards.
- Mark these items with X’s and those with Z’s.
- Your 3’s look like 8’s.
- How many and’s can you put in one sentence?
- My typewriter smudged all the &’s in my letter.
