Epicycloid vs. Hypocycloid

Epicycloidnoun

(geometry) The locus of a point on the circumference of a circle that rolls without slipping on the circumference of another circle.

Epicycloidnoun

A curve traced by a point in the circumference of a circle which rolls on the convex side of a fixed circle.

Epicycloidnoun

a line generated by a point on a circle rolling around another circle

Epicycloid

In geometry, an epicycloid is a plane curve produced by tracing the path of a chosen point on the circumference of a circle—called an epicycle—which rolls without slipping around a fixed circle. It is a particular kind of roulette.

Hypocycloidnoun

(geometry) The locus of a point on the circumference of a circle that rolls without slipping inside the circumference of another circle.

Hypocycloidnoun

A curve traced by a point in the circumference of a circle which rolls on the concave side in the fixed circle. Cf. Epicycloid, and Trochoid.

Hypocycloidnoun

a line generated by a point on a circle that rolls around inside another circle

Hypocycloid

In geometry, a hypocycloid is a special plane curve generated by the trace of a fixed point on a small circle that rolls within a larger circle. As the radius of the larger circle is increased, the hypocycloid becomes more like the cycloid created by rolling a circle on a line.