What is the definition of an adverbial clause?

An adverbial clause is defined as a group of words that functions as an adverb by modifying verbs, adjectives, or other adverbs in a sentence, providing context such as time, place, reason, condition, or manner. For example, in the sentence "She sings beautifully because she practices regularly," the clause "because she practices regularly" specifies the reason for her singing beautifully, thus functioning in an adverbial capacity.

This highlights how adverbial clauses can enrich sentences by adding essential information related to the action being described, showing their critical role in providing clarity and detail. In contrast, other options describe different parts of speech, such as noun clauses functioning as subjects or objects, and adjective clauses modifying nouns, which do not align with the function of adverbial clauses.