Relative pronoun

A relative pronoun is a pronoun that introduces an adjective clause. The relative pronouns in English are:

• who - used if the pronoun refers to a person or personified entity
• whose - the possessive pronoun (often confused with "who's", which is a contraction for "who is".
• whom - in formal English, the objective case of who
• which - used to introduce a nonrestrictive clause if the pronoun refers to an inanimate object
• that - used to introduce a restrictive clause and can refer only to inanimate objects in some speakers' idiolects