cassinian oval

GNU Webster's 1913

1. n. (Geom.) the locus of a point the product of whose distances from two fixed points is constant; -- so called from Cassini, who first investigated the curve. Thus, in the diagram, if P moves so that P A.P B is constant, the point P describes a Cassinian oval. The locus may consist of a single closed line, as shown by the dotted line, or of two equal ovals about the points A and B.