A pronoun that introduces a relative clause and refers to an antecedent. The interrogative pronouns can be used as relative pronouns: what, which, who, whom, and whose
a pronoun (as `that' or `which' or `who') that introduces a relative clause referring to some antecedent
A relative pronoun is a word such as `who', `that', or `which' that is used to introduce a relative clause. `Whose', `when', `where', and `why' are generally called relative pronouns, though they are actually adverbs. A pronoun that introduces a relative clause and has reference to an antecedent, as who in the child who is wearing a hat or that in the house that you live in. a pronoun such as 'who', 'which', or 'that' by which a relative clause is connected to the rest of the sentence
French - Turkish
Definition of pronom relatif in French Turkish dictionary