hypotrochoid
Hy`po*tro"choid, n. Etym: [Pref. hypo- + trochoid.] (Geom.) Defn: A curve, traced by a point in the radius, or radius produced, of a circle which rolls upon the concave side of a fixed circle. See Hypocycloid, Epicycloid, and Trochoid.
Hy`po*tro"choid, n. Etym: [Pref. hypo- + trochoid.] (Geom.) Defn: A curve, traced by a point in the radius, or radius produced, of a circle which rolls upon the concave side of a fixed circle. See Hypocycloid, Epicycloid, and Trochoid.