10.1.12. Apostrophe

Apostrophes mark the possessive form, contractions or the plurals of single lower-case letters.

1. The possessive form of any singular noun and of plural nouns not ending in the letter ‘s’ is marked by an apostrophe followed by the letter ‘s’:

   an actress’s role

   the owner’s car

   women’s rights

   the MEP’s expenses

   After a plural ending in the letter ‘s’, however, the possessive ‘s’ is omitted:

   footballers’ earnings

   the MEPs’ expenses

   There is no apostrophe in possessive pronouns:

   its (as distinct from it’s, i.e. ‘it is’), ours, theirs, yours

   Some place names containing a possessive omit the apostrophe (Earls Court, Parsons Green), while others retain it (St John’s Wood, King’s Lynn). See the New Oxford Dictionary for Writers and Editors for individual cases.

2. Contractions. Apostrophes are also used to indicate contractions, i.e. where one or more letters have been omitted from a word or where two words have been joined together. Contractions are common in informal texts, but should not be used in formal texts. For example:

   don’t = do not

   it’s = it is (as distinct from the possessive pronoun ‘its’)

   who’s = who is (as distinct from the possessive pronoun ‘whose’)

   you’re = you are (as distinct from the possessive pronoun ‘your’)

3. The plurals of single lower-case letters take an apostrophe to avoid misunderstanding:

   Dot your i’s.

   Mind your p’s and q’s.