フランス語のencore、アンコールから。ラテン語のhanc horamから、hancはここから、horamは時間から。
Whenever any Gentlemen are particularly pleased with a Song, at their crying out Encore ... the Performer is so obliging as to sing it over again. [Steele, "Spectator" No. 314, 1712]As a noun, from 1763; as a verb, from 1748. Related: Encored.
There appears to be no evidence that either the Fr. or It. word was ever similarly used in its native country. The corresponding word both in Fr. and It. is bis; in It. da capo was formerly used. [OED]