nounclause

A noun clause is a dependent clause that functions as a noun within a larger sentence. It can serve as the subject, object, complement, or appositive of a clause. In many grammars, noun clauses are a subtype of embedded clauses introduced by complementizers or by wh- words and behave like noun phrases.

In English, noun clauses are typically finite clauses introduced by that, whether, or if, or by wh- words that form wh- clauses. Examples: That he left early surprised me. I know what you did. Whether she will come is uncertain. What you decided matters. The complementizer that is often optional in informal speech, as in I think (that) you are right.

Common functions and positions include: subject position (That she left affected the schedule), direct object (She acknowledged that the plan failed), object of a preposition (We discussed whether we should go), and subject complement or appositive (The issue is whether we can fund it).

Note that some grammars distinguish noun clauses from gerund phrases or other non-finite clauses, especially when the subordinate clause lacks a finite verb form. Cross-linguistic variation exists: many languages use dedicated complementizers, and some allow multiple subordinators for content clauses. Overall, noun clauses play a central role in encoding propositions and information within larger sentences.