An Etymological Dictionary of Astronomy and Astrophysics

A shape of constant width created using an equilateral triangle and three similar circles. The equilateral triangle lies in the first circle with a vertex coinciding with the center of the circle and the sides equal to the circle radius. The centers of the two other circles are located at the two other vertices. The Reuleaux triangle is the intersection of the three circles.

See also: Named after Franz Reuleaux (1829-1905), a German engineer, specialist of analysis and design of mechines; → triangle.