(1):

(n.) A call or demand (as, by continued applause) for a repetition; as, the encores were numerous.

(2):

(v. t.) To call for a repetition or reappearance of; as, to encore a song or a singer.

(3):

(adv. / interj.) Once more; again; - used by the auditors and spectators of plays, concerts, and other entertainments, to call for a repetition of a particular part.