roulette

1. (uncountable) A game of chance in which a small ball is made to move round rapidly on a circle divided off into numbered (usually red and black) spaces. When the ball stops, it indicates the result of a variety of wagers permitted by the game.Synonyms: roly-poly

2. (uncountable, figuratively) An instance of risk-taking, especially when the downside exceeds the upside (contrary to the game of roulette where only the wager is lost).Examples: "Doctors and health officials said that the WRC-TV documentary, "DPT: Vaccine Roulette," emphasized the risks of the vaccine while ignoring the dangers of the disease, which has been almost wiped out in this country."; "They would all rather take their chances with the existing policy-making roulette rather than follow process discipline."; "By contrast giving treatments open-label slows everything down by leading us up blind alleys while playing roulette with our patients' lives."

3. (countable) A small toothed wheel used by engravers to roll over a plate in order to produce rows of dots.

4. (countable) A similar wheel used to roughen the surface of a plate, as in making alterations in a mezzotint.

5. (countable, geometry) The locus of a point on a plane curve that rolls without slipping along another fixed plane curve.

6. (philately) Any of the small incisions on a sheet of stamps, used as an alternative to perforations.