Meaning of aclinic line

a•clin'ic line'

Pronunciation: (ā-klin'ik), [key]
  1. an imaginary line on the surface of the earth, close and approximately parallel to the equator, connecting all those points over which a magnetic needle shows no inclination from the horizontal. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.