subclause

A subclause, or subordinate clause, is a clause that cannot stand alone as a complete sentence and depends on a main clause to express a full thought. Subclauses function within larger sentences to add information such as what is believed, when something happens, where, why, or under what conditions.

Types include noun clauses, relative clauses, and adverbial clauses. A noun clause acts as a noun within the sentence: “What you said surprised everyone.” Here “What you said” is a noun clause. A relative clause describes a noun: “The book that you lent me” uses “that you lent me” as a subordinate clause. An adverbial clause modifies the main clause and conveys time, condition, reason, or manner: “If it rains, we will cancel” uses “If it rains” as a subordinate clause.

Conjunctions and relative pronouns introduce subclauses: subordinate conjunctions (that, if, because, when, although) and relative pronouns (who, which, that). Subclauses are linked to the main clause by syntactic dependency and are typically marked off by punctuation when placed at the beginning of a sentence.

In complex sentences, subclauses provide nuance and specificity, and they are used across languages with varying rules about order and punctuation. In legal and contractual writing, subclauses may denote subdivisions within a clause, labeled as subclauses (e.g., Subclause 4.2).