epicycloid
/ˌɛpɪˈsaɪklɔɪd/
noun
- A curve traced by a point on the edge of a circle as it rolls around the outside of a fixed circle.
- Some gears are shaped like an epicycloid to reduce friction and wear.
- The math teacher drew an epicycloid on the board to show how the curve is formed.
- The pattern of the flower's petals resembled an epicycloid when viewed from above.