'Hypocycloid' definitions:

Definition of 'hypocycloid'

(from WordNet)
noun
A line generated by a point on a circle that rolls around inside another circle

Definition of 'Hypocycloid'

From: GCIDE
  • Hypocycloid \Hy`po*cy"cloid\, n. [Pref. hypo- + cycloid: cf. F. hypocyclo["i]de.] (Geom.) 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. [1913 Webster]