n.1 a gambling game using a table in which a ball is dropped on to a revolving wheel with numbered compartments, players betting on the number at which the ball comes to rest.
2 Math. a curve generated by a point on a curve rolling on another.
3 a a revolving toothed wheel used in engraving. b a similar wheel for making perforations between postage stamps in a sheet.
Derivatives:
rouletted adj. (in sense 3b).
Etymology: F, dimin. of rouelle f. LL rotella dimin. of L rota wheel