∙ 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. uncountable
∙ A small toothed wheel used by engravers to roll over a plate in order to produce rows of dots. countable
∙ A similar wheel used to roughen the surface of a plate, as in making alterations in a mezzotint. countable
∙ The locus of a point on a plane curve that rolls without slipping along another fixed plane curve. countable, geometry
∙ Any of the small incisions on a sheet of stamps, used as an alternative to perforations. philately
Verb
∙ To separate or decorate by incisions made with a small toothed wheel.