whose

Whose is a word in English that functions as both a determiner and an interrogative or relative pronoun. It expresses possession and is used to ask who owns something or to introduce a clause that specifies the owner of a noun. Although it often refers to people, whose can modify nouns representing animals or inanimate things when possession is indicated.

Historically, whose derives from the Old English genitive form hwæs, related to who. It is cognate with German wessen and Dutch wiens, among other Germanic forms. In modern English, whose remains the standard possessive form associated with who, used in both questions and relative clauses.

As an interrogative determiner, whose precedes a noun: “Whose jacket is this?” As a relative determiner or pronoun, whose introduces a relative clause: “The author whose books I enjoy will visit” or “The author, whose books I enjoy, will visit.” In both roles, whose shows possession by a person or thing that is the antecedent in the clause. Whose is not a contraction and should not be confused with who’s, the contraction of who is or who has.

Common confusion arises with the contraction who’s. If you can replace whom with who is or who has in the sentence, you would use who’s; otherwise, use whose. Whose can also refer to possessions of animals or inanimate things when ownership is specified, though it often sounds more natural to mention the possessor directly (for example, “the dog whose owner spoke”). In formal writing, both restrictive and nonrestrictive relative clauses may use whose, with commas in nonrestrictive cases (The engineer, whose plan was approved, spoke).