Meaning of conchoid

con•choid

Pronunciation: (kong'koid), [key]
— n. Geom.
  1. a plane curve such that if a straight line is drawn from a certain fixed point, called the pole of the curve, to the curve, the part of the line intersected between the curve and its asymptote is always equal to a fixed distance. Equation:= b ± a sec &thgr;. r
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.