Dictionary entry

Trochoid

Webster's Dictionary 1913

Tro″choid (?), n. [Gr. � a wheel + -oid; cf. F. trochoïde. See Troche.] (Geom.) The curve described by any point in a wheel rolling on a line; a cycloid; a roulette; in general, the curve described by any point fixedly connected with a moving curve while the moving curve rolls without slipping on a second fixed curve, the curves all being in one plane. Cycloids, epicycloids, hypocycloids, cardioids, etc., are all trochoids.