A dependent clause is a group of words that contains a subject and a verb but cannot stand alone as a complete sentence. It relies on an independent clause to provide a complete thought. For example, in the sentence "Although it was raining, we went for a walk," the phrase "Although it was raining" is a dependent clause. Dependent clauses often begin with subordinating conjunctions like although, because, or when. These words signal that the clause is not a complete thought. Understanding dependent clauses is essential for constructing complex sentences and enhancing writing clarity.