A clause is a grammatical unit that contains a subject and a predicate (verb). It can stand alone as a complete thought, known as an independent clause, or it can be part of a larger sentence, as in the case of dependent (or subordinate) clauses. Clauses help to express complex ideas in writing, and they can add information, indicate conditions, or signal time.
The word "clause" comes from the Latin word "clausula," meaning "a closing" or "a key phrase," which itself is derived from "claudere," meaning "to close." This reflects how clauses combine to form sentences and express complete ideas.