A dependent clause (or subordinate clause) cannot stand alone as a sentence. In itself, a dependent clause does not express a complete thought; therefore, it is usually attached to an independent clause. Although a dependent clause contains a subject and a predicate, it sounds incomplete when standing alone.
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Noun 1. 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 (synonym) dependent clause (hypernym) clause (hyponym) restrictive clause (part-holonym) complex sentence