Roulette

Roulette, in mathematics, the locus of a point carried on a curve which rolls on another (fixed) curve. The name appears to have been used by Pascal to denote the cycloid, which is the simplest roulette, being traced by a point on the circumference of a circle rolling on a straight line. The trochoids and epicycloids (q.v.) are also simple roulettes, the latter being traced by points on a circle which rolls on another circle.

See W. H. Besant, Roulettes and Glissettes.