A set shown one at a time in a turning order. It offers everything and shows almost nothing at once.
French carrousel, from Italian carosello, the name of a mounted tournament game; the deeper root of the Italian word is disputed, but the game's turning, one-at-a-time procession is the sense that survives into modern usage.
A set of things shown one at a time in a turning order — it offers everything it holds and shows almost none of it at once.