The etymology of the word 'adverb' is the Latin 'ad-' meaning 'to' and 'uerbum', a verb or word. An adverb is usually attached to a verb, modifying or qualifying it. It tells us the way in which the action of the verb is carried out. It may also modify an adjective as in the case of the word 'very'. A VERY silly child.
Adverbs usually express a relation of place, time, manner, number or degree with the verb.