from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An imaginary line on the earth's surface connecting points where the magnetic declination is zero.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A line on a chart or map joining points of zero magnetic declination.
from the GNU version of the Collaborative International Dictionary of English
- adj. an imaginary line on the earth's surface passing through those places where the magnetic needle points to the true north; the line of no magnetic variation. There is one such line in the Western hemisphere, and another in the Eastern hemisphere.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an imaginary line connecting points on the Earth's surface where the magnetic declination is zero
agonic + line (Wiktionary)