dependent clause

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A clause that cannot stand alone as a full sentence and functions as a noun, adjective, or adverb within a sentence.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun grammar A subordinate clause.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a clause in a complex sentence that cannot stand alone as a complete sentence and that functions within the sentence as a noun or adjective or adverb