What is a clause?

A clause is a closely related group of words that includes both a subject and a verb.
The work was difficult, but the results were worth it.

Clauses contrast with phrases, which do not have subjects and verbs.

An independent clause expresses a complete thought and can stand on its own as a sentence.

Jack painted the fence.
Jack painted the fence, but with the wrong paint.

A dependent clause contains a subject and verb but does not express a complete thought and cannot stand on its own. A dependent clause relies on an independent clause to complete its meaning. In these examples, the independent clause is in boldface and the dependent clause is italicized.

The movers ruined the china cabinet that belonged to my great-grandmother.
My best friend, who paints oil and watercolors, has a show at the art gallery.

Dependent clauses are often introduced by either a subordinating conjunction or a relative pronoun. Dependent clauses introduced by a subordinating conjunction are called subordinate clauses, and those introduced by relative pronouns are called relative clauses.

Clauses serve a variety of functions in a sentence. They can act as nouns (subjects or objects), adjectives, or adverbs.