An adverb is a part of speech which modifies a verb, an adjective or another adverb. It often answers the question of how something is done (and may refer to the time, intensity, or manner).

Example: PHP 4:10
Ἐχάρην δὲ ἐν κυρίῳ μεγάλως
Echarēn de en kyriō megalōs
I rejoice but in (the) Lord greatly
I greatly rejoice in the Lord