What do you call a word that usually modifies a verb but can sometimes modify an adjective?

An adverb is a Word that modifies a verb, an adjective, or another adverb. Examples:

modifying the verb: We really like that restaurant.

modifying the adjective: Juanita is a really smartgirl.

modifying the adverb: That was really very nice of you.

modifying a verb: John carefully Worded the answer to the question.

modifying an adjective: John wrote a carefully Worded answer to the question.

modifying an adverb: John wrote a very carefully Worded answer to the question.