a punctuation mark (') used to indicate either possession (e.g. Harry's book; boys' coats) or the omission of letters or numbers (e.g. can't; he's; 1 Jan. '99)

a brief lecture on the correct use of apostrophes

misplaced commas and apostrophes may be acceptable in text messages

an exclamatory passage in a speech or poem addressed to a person (typically one who is dead or absent) or thing (typically one that is personified)

Lanyer's apostrophe to Mary

Wordsworth's apostrophe to Imagination