Adverbial

Disambiguation: adverbial is also an adjective that means "relating to an adverb".

An adverbial (/ædvɜ:(r)bɪəl/) or adverbial phrase (/ædvɜ:(r)bɪəl freɪz/) is a phrase that functions as an adverb; its syntactic function is to modify other expressions, including verbs, adjectives, other adverbials (including adverbs), and sentences - i.e. it says when, where or how something happens.

• Time adverbial (when)
• Manner adverbial (how)
• Place adverbial (where)
• Manner adverbials

Grammatically:

• An adverb phrase, i.e. a phrase with an adverb as its head can be used as an adverbial.
  • An adverb phrase can consist of a single word phrase; i.e. a single adverb.
• It can be a prepositional phrase, or sometimes just a single word preposition, i.e. a prepositional phrase adverbial
• It can be a noun phrase, making a noun phrase adverbial.
• It can be an adverbial clause

Compare adjectival.