What is "adverbial phrase"

n. (context grammar English) A phrase that collectively modify a verb, adjective, another adverb, or a prepositional phrase.

In linguistics, an adverbial phrase is a group of two or more words operating adverbially, meaning that their syntactic function is to modify a verb, an adjective, or an adverb. Adverbial phrases ("AdvP" in syntactic trees) are phrases that do the work of an adverb in a sentence.