A punctuation mark used to indicate either possession or omission of letters and numbers.

The two main uses of apostrophes are:

  • apostrophe of possession indicates that a noun owns something (for example, ‘the student’s work’, ‘David’s phone’). Plural nouns that end with -s have an apostrophe added after the -s (for example, ‘the teachers’ staff room’).
  • apostrophe of contraction replaces omitted letters in a word (for example, ‘isn’t’, ‘don’t’, ‘he’s’).