Subordinate (clause)

also called sub-clause, embedded clause, or dependent clause.

a clause that cannot stand alone as a sentence. Instead, it performs a particular function in a sentence.

For example, a subordinate clause may function as a circumstantial, a subject, or an object.

See independent clause.

Crystal, David. Rediscover Grammar, page 45.

Bruntt, Karen and Bryanne, Ulla. Handbook for Grammar Detectives, page 114-115.