1. an imaginary line connecting points on the Earth's surface where the magnetic declination is the same; [syn: isogonic line, isogonal line, isogone]
WordNet (r) 3.0 (2006):
isogonal line
n 1: an imaginary line connecting points on the Earth's surface
where the magnetic declination is the same [syn: isogonic
line, isogonal line, isogone]