isopiestic line vs isogram

isopiestic line and isogram both are nouns.

Word	Noun	Adjective	Verb	Adverb
isopiestic line	Yes	No	No	No
isogram	Yes	No	No	No

As nouns, isogram is a hypernym of isopiestic line; that is, isogram is a word with a broader meaning than isopiestic line:

isopiestic line: a line on a map connecting places with equal ground water pressure.
isogram: a line drawn on a map connecting points having the same numerical value of some variable

Other hypernyms of isopiestic line include isarithm, isopleth.

isopiestic line (noun)	isogram (noun)
a line on a map connecting places with equal ground water pressure.	a line drawn on a map connecting points having the same numerical value of some variable