/huy perr"beuh leuh/ , n. Geom.
the set of points in a plane whose distances to two fixed points in the plane have a constant difference; a curve consisting of two distinct and similar branches, formed by the intersection of a plane with a right circular cone when the plane makes a greater angle with the base than does the generator of the cone. Equation: x 2 / a 2 - y 2 / b 2 = ±1. See diag. under conic section .
[ 1660-70; hyperbolé the geometrical term, lit., excess. See HYPERBOLE ]