A curve traced by a point in the circumference of a circle which rolls on the convex side of a fixed circle.
A curve generated by the motion of a point on the circumference of circle which rolls on the convex side of a fixed circle.
a line generated by a point on a circle rolling around another circle
a path generated by a circle on a circle, which is how this tooth profile is produced
In geometry, an epicycloid is a plane curve produced by tracing the path of a chosen point of a circle — called epicycle — which rolls around without slipping around a fixed circle. It is a particular kind of roulette.