An apostrophe is a punctuation mark that is usually used to show that something belongs to someone or something. It can also be used to show when letters or numbers are missing from a word or to make contractions. Full definition
By Chris Saylor Last week, I talked about formatting dialogue within dialogue, as part of an attempt to address a request about using apostrophes in fiction. (marcykennedy.com)
Then there are those obsessed by the use of apostrophes in signs. (totalpolitics.com)
There are lessons on possessive apostrophes for singular and plural possession, comparatives and speech layout and punctuation. (tes.com)