[noun](broadcasting industries) a method of preparing recorded material for a music performer (a singer or instrument player) and playing it back when the performer performs
[noun] a karaoke machine, a music playback machine that plays popular tunes with the lead vocals audio missing or removed, and often with a video screen showing the song lyrics highlighted in time with the music
(This term, 空オケ, is an alternative spelling (rare) of the above term.)