Use an apostrophe when combining or shortening words by omitting one or more letters:
Note: Contractions are considered inappropriate in formal writing, including some academic writing. Check with your instructor if you are not sure whether contractions are acceptable in your class.
Use an apostrophe to form possessive nouns. Some possessive nouns are formed by adding an apostrophe followed by the letter S; others are formed by adding only an apostrophe:
Note: Possessive pronouns do not use apostrophes. Pronouns containing apostrophes are always contractions:
