Meaning of isopor

i•so•por

Pronunciation: (ī'su-pôr"), [key]
— n.
  1. an imaginary line on the earth's surface connecting points of equal annual change in the declination, inclination, or other components of the earth's magnetic field. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.