Latency

You’ll see this term used in a variety of contexts, but it means essentially the same thing: Latency is the amount of time it takes for a device to respond to a command. In a MIDI instrument, it might be the time between a “note on” message being sent, to when that note actually sounds (might be different figures for single notes, chords, or multitimbral operation). In a hard drive, there is rotational latency; in a hard disk recording system, there is latency in getting all the tracks to sound, and so on.