A relative pronoun is a pronoun that marks a relative clause within a larger sentence.

A relative pronoun links two clauses into a single complex clause. To this extent, it is similar in function to a subordinating conjunction. Unlike a conjunction, however, a relative pronoun stands in place of a noun. Compare:

(1) This is a house. Jack built this house.

(2) This is the house that Jack built.

Sentence (2) consists of two clauses, a main clause (This is the house) and a relative clause (that Jack built). The word that is a relative pronoun. Within the relative clause, the relative pronoun stands for the noun phrase it references in the main clause, which is one of the arguments of the verb in the relative clause. In the example, the argument is the house, the direct object of built.

Other arguments can be relativised using relative pronouns:

Subject: Jack is the boy who kissed Jenny.

Indirect object: Jack is the boy that Jenny gave a gift to.

Adpositional complement: Jack built the house in which I now live.

Possessor: Jack is the boy whose friend built my house.

Not all languages have relative pronouns. Those that do tend to use words which originally had other functions; for example, the English which is also an interrogative word. There appears to be no language in the world with a distinct word used only as a relative pronoun. This suggests that relative pronouns are a fairly late development in the history of language.

Relative pronouns may or may not agree with the antecedent. In Spanish, for example, some relative pronouns agree in gender and number with the noun they modify. In English, different pronouns are sometimes used if the antecedent is a human being (as opposed to a non-human or an inanimate object). In other languages, the relative pronoun is an invariable word.

See also

• For specific discussion of English usage: English relative clauses or English grammar.
• Relative pronouns in Spanish