what is a relative clause

A relative clause is a type of dependent clause that modifies a noun or noun phrase and gives more information about it. It cannot stand alone as a sentence and always begins with a relative pronoun, such as who, whom, that, which, or whose. There are two types of relative clauses: restrictive and nonrestrictive. Restrictive relative clauses provide essential information about the noun or noun phrase, while nonrestrictive relative clauses provide additional, nonessential information. Relative clauses can be introduced by relative pronouns or other grammatical devices, depending on the language. In English, relative clauses are often used to combine two independent clauses into one sentence and are also known as adjective clauses.