Definitions for "Relative clause"
An adjective clause introduced by a relative pronoun: the programs that provide services; the teacher who gives all A?s.
a clause that begins with a relative pronoun and functions as an adjective.
a clause which qualifies or restricts the meaning of the noun in a noun phrase. It may be introduced by words such as who, which and that in English: the man who I saw this morning, the woman (that) I sent the letter to.