isogeotherm vs isarithm

isogeotherm and isarithm both are nouns.

Word	Noun	Adjective	Verb	Adverb
isogeotherm	Yes	No	No	No
isarithm	Yes	No	No	No

As nouns, isarithm is a hypernym of isogeotherm; that is, isarithm is a word with a broader meaning than isogeotherm:

isogeotherm: an isogram connecting points of equal temperature below the surface of the earth.
isarithm: a line drawn on a map connecting points having the same numerical value of some variable

Other hypernyms of isogeotherm include isogram, isopleth.

isogeotherm (noun)	isarithm (noun)
an isogram connecting points of equal temperature below the surface of the earth.	a line drawn on a map connecting points having the same numerical value of some variable