What clause relies on the rest of sentence in order to express a complete thought?

The clause that relies on the rest of the sentence to express a complete thought is called a dependent clause or subordinate clause.

Here's why:

* Dependent clauses cannot stand alone as a complete sentence. They lack a subject and verb combination that can convey a complete idea.

* They are dependent on an independent clause (a complete sentence) to make sense.

Example:

* Dependent Clause: *Because the rain was heavy.* (This doesn't make sense on its own.)

* Independent Clause: *The game was canceled.* (This is a complete thought.)

Combined Sentence: *Because the rain was heavy, the game was canceled.*

Here, the dependent clause "Because the rain was heavy" adds information to the independent clause, but it can't exist without it.