Prerecording is the -ing form of prerecord: the act of recording music, a programme, or a message so it can be used later. Studios talk about prerecording the vocals, prerecording the applause, prerecording a segment for next week. It also works as a noun for the thing you already made: “use the prerecording,” “we have a prerecording of the speech.” Same idea as the verb — not live, stored, ready to play. In casual speech people often just say recording; prerecording is the clearer word when you need to contrast it with a live take. Though actually a “live” broadcast may still rest on prerecordings underneath, so the label is about when it was captured, not how exciting it feels.