/toor bil"yeuhn/ , 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 .
[ 1470-80; earlier turbilloun to ( u ) rbillon turbilionem, dissimilated var. of * turbinionem, acc. of * turbinio whirlwind. See TURBINE, -ION ]