\Pol`y*con"ic\, a. [Poly- + conic.]
Pertaining to, or based upon, many cones.
{Polyconic projection} (Map Making), a projection of the
   earth's surface, or any portion thereof, by which each
   narrow zone is projected upon a conical surface that
   touches the sphere along this zone, the conical surface
   being then unrolled. This projection differs from conic
   projection in that latter assumes but one cone for the
   whole map. Polyconic projection is that in use in the
   United States coast and geodetic survey.