Appropriate Uses of the Apostrophe

Singular Possessive Case

• A singular noun or indefinite pronoun (for example, anyone, everything) shows possession by the addition of the apostrophe and s, so it is correct to write "the boy's book," "the man's car" and "anyone's guess."

  To check if the possessive is the correct case, change the word order around, and if you have to use "of," then it is the possessive case. For example, the book of the boy and the car of the man.

  If the the singular noun ends in s, then either use the apostrophe without the additional s, or add both, such as "Keats' life" or "Keats's life."

  Teachers and examiners may have a strong preference, so get advice from them on which they prefer.

Plural Possessive Case

• If the plural noun does not end in s, add apostrophe s. So it is correct to write "the children's books"' and "people's hats."

  The most common letter ending of a plural is s, and here you add the apostrophe but not an additional s. For example, " the neighbors' children," "the doors' handles."

Other Possessives

• Words such as his, hers, theirs and so forth are not followed by an apostrophe. They indicate possession but are a special class of specific words (possessive pronouns). Writing "his book" and "their book" is the correct form.

  If there are two nouns sharing possession, then the 's is only used on the second, as in "John and Jerry's racehorse" or "Sherlock and Watson's apartment."

  Sometimes the connection is one of description, not possession, as in "the accounts department" or "sports car."

Missing Letters

• The written language sometimes mimics the spoken language where shortcuts are often taken. The apostrophe can be used to indicate missing letters: I've = I have; it's = it is, or it has depending on the context, while could've = could have.

  When proofreading, a good test is to look for all the words ending in s and decide if they are a plural, possessive or have another function.

Other Uses of the Apostrophe

• A foreign word that is pronounced with a glottal stop (not used in English) will be transcribed to indicate this such as "Qur'an." Some expressions use the apostrophe by convention, as in "mind your p's and q's."

  Periods of years do not take an apostrophe, so while the "1980s" is correct, the "1980's" is not.