THE APOSTROPHE [ ' ]

The main use of the apostrophe is to form the possessive case of most nouns by adding an apostrophe or an apostrophe and 's'. See also Possessives for more information. Punctuation used to denote a sudden change or break in a sentence, e.g. He was gone — heaven forbid — for an hour and no one knew where he was. Spaces may or may not be added before or after a dash, but the use of spaces must be consistent. Do not combine a dash with a colon, comma, or semicolon. Apply the following rules when using the apostrophe.

To begin, find out about the purposes for which the apostrophe is used. Click on a link below to read the rules and see examples, take a guided tour by clicking the 'start' button below.

1. The apostrophe is used when leaving out a letter or number in a contraction, e.g. can't, wouldn't.
2. The apostrophe is used for omitted letters, e.g. rock 'n' roll, and for omitted numbers, e.g. the class of '72, the '20s.
3. The apostrophe is used for plurals of letter abbreviations with periods and single letters, e.g. p's and q's, two A's and four B's. Plurals of multi-letter combinations and plurals of numerals end in s with no apostrophe, e.g. VIPs, 1000s.
4. The possessive of singular nouns ending in s, including nouns ending in s, x, z, ch, or sh, is formed by adding 's, e.g. witness's affidavit. However, if the next word begins with s, then add only an apostrophe, e.g. witness' story.
5. The possessive of singular nouns not ending in s is formed by adding 's, e.g. VIP's seat, baby's food.
6. The apostrophe follows the s of a word with two sibilant sounds, e.g. Kansas', Moses'.
7. The apostrophe is added for the possessive of a noun that is plural in form but singular in meaning, e.g. mathematics' formulas.
8. The apostrophe follows the s for the possessive of plural nouns that end in s, e.g. girls' movies. For the possessive of a plural noun that does not end in s, add 's, e.g. women's rights.
9. For singular proper nouns, add only an apostrophe for the possessive, e.g. Achilles' heel.
10. No apostrophe is used for personal pronouns like hers, his, its, mine, ours, theirs, whose, your, yours. Indefinite pronouns require an apostrophe, e.g. one's lover. For other pronouns like another and others, follow the rule for singular and plural, e.g. another's and others'.
11. For joint possession, the 's is added to the word nearest the object of possession, e.g. Francis and Kucera's book.
12. The apostrophe is not used in names of organizations unless actually part of the legal name. The apostrophe is not used in plurals of numerals or multiple-letter combinations.