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.
- A curve traced by a point on or connected with a circle as the circle rolls along a fixed straight line.
- Capable of or exhibiting rotation about a central axis.
- Permitting rotation, as a pulley or pivot.