The word "adverb" is a noun. An adverb, a word that modifies a verb, adjective, or adverb, is its own part of speech.
adverb
Adverb
Adverb
adverb
"Ever" is an adverb.
Twice is an adverb.
Commonly is an adverb.
Beautifully is an adverb.
Hysterically is an adverb.
adverb
Recently is an adverb.
Beautifully is an adverb.