What is noun clause and adjective clause

A sentence which contains just one clause is called a simple sentence.

A sentence which contains one independent clause and one or more dependent clauses is called a complex sentence. (Dependent clauses are also called subordinate clauses.)

There are three basic types of dependent clauses: adjective clauses, adverb clauses, and noun clauses. (Adjective clauses are also called relative clauses.)

This page contains information about adjective clauses.