Adverbial \Ad*ver"bi*al\, a. [L. adverbialis: cf. F. adverbial.] Of or pertaining to an adverb; of the nature of an adverb; as, an adverbial phrase or form.
adverbial adj : of or relating to or functioning as an adverb; "adverbial syntax" adverbial n : a word or group of words function as an adverb