Pronunciation: (toor-bil'yun),[key] —n. 1. a whirlwind or something resembling a whirlwind.
2. a firework that rises spirally.
3. Horol.a frame for the escapement of a timepiece, esp. a watch, geared to the going train in such a way as to rotate the escapement about once a minute in order to minimize positional error. Cf. karrusel.