polyconic : Idioms & Phrases

• noun a conic projection of a map having distances between meridians equal to those distances on a globe
  

WordNet

• (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.

Webster 1913