isothere vs isarithm

isothere and isarithm both are nouns.

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

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

isothere: a line on a map linking places with the same mean summer temperature.
isarithm: a line drawn on a map connecting points having the same numerical value of some variable

Other hypernyms of isothere include isogram, isopleth.

isothere (noun)	isarithm (noun)
a line on a map linking places with the same mean summer temperature.	a line drawn on a map connecting points having the same numerical value of some variable