adverbial adverbial /ædˈvɜːrbiəl/

adjective

1. () Of or relating to or functioning as an adverb  ( adverbial )
   of or relating to or functioning as an adverb
    Adverbial syntax
   adverbial syntax
   

noun

1. A word or group of words function as an adverb  ( adverbial )
   a word or group of words function as an adverb