CLAUSE: A group of related words which contains both a subject and a predicate.
An independent clause contains both a subject and a predicate, and it expresses a complete thought.
A subordinant/dependent clause contains both a subject and a predicate, but does not expresses a complete thought. It can function as an adjective, adverb, or noun.
Beginning with a relative pronoun (who, whom, which, that), a relative clause functions as an adjective.
A noun clause acts as a noun in a sentence.
An adverbial clause acts as an adverb, answering questions like who, what, when, where, why, to what degree, and under what conditions.