*roulette*

n. [ F., properly, a little wheel or ball. See Rouleau, Roll. ] 1. A game of chance, in which a small ball is made to move round rapidly on a circle divided off into numbered red and black spaces, the one on which it stops indicating the result of a variety of wagers permitted by the game. [ 1913 Webster ]

2. (Fine Arts) (a) A small toothed wheel used by engravers to roll over a plate in order to order to produce rows of dots. (b) A similar wheel used to roughen the surface of a plate, as in making alterations in a mezzotint. [ 1913 Webster ]

3. (Geom.) the curve traced by any point in the plane of a given curve when the latter rolls, without sliding, over another fixed curve. See Cycloid, and Epycycloid. [ 1913 Webster ]

4. A small toothed wheel used to make short incisions in paper, as a sheet of postage stamps to facilitate their separation. [ Webster 1913 Suppl. ]