i should also mention that my reasoning comes from audio engineering terminology. when you have a live show of anything using sound (can be a concert, theme park show, a play on a stage,what ever.) you have a play list of what audio to play at what time. a musical group usually just has a set list of what songs they are playing but in the case of a theater show that requires sound effects or music you would have all your sound files queued in a patch bay or playback device of some kind so when the actor starts singing or what have you, you can hit,lets say,patch A4 for what ever song. i say queue because every song you play in a live venue has to be loaded and ready to hit its mark. if you don't do it ahead of time you might have a bad bit of audio or a glitch that gos blaring over the load speakers. that being said, i don't really know what context the author was using,just the one that makes sense to me.
