isogonal line vs isogone

isogonal line and isogone both are nouns.

Word	Noun	Adjective	Verb	Adverb
isogonal line	Yes	No	No	No
isogone	Yes	No	No	No

As nouns, isogonal line and isogone are synonyms defined as:

isogonal line and isogone: an imaginary line connecting points on the Earth's surface where the magnetic declination is the same

Other synonyms of isogonal line include isogonic line.

isogonal line (noun)	isogone (noun)
an imaginary line connecting points on the Earth's surface where the magnetic declination is the same	an imaginary line connecting points on the Earth's surface where the magnetic declination is the same