femtovolt vs potential unit

femtovolt and potential unit both are nouns.

Word	Noun	Adjective	Verb	Adverb
femtovolt	Yes	No	No	No
potential unit	Yes	No	No	No

As nouns, potential unit is a hypernym of femtovolt; that is, potential unit is a word with a broader meaning than femtovolt:

femtovolt: a unit of potential equal to one quadrillionth of a volt (or one thousandth of a picovolt)
potential unit: a measure of the potential energy of a unit charge at a given point in a circuit relative to a reference point (ground)

femtovolt (noun)	potential unit (noun)
a unit of potential equal to one quadrillionth of a volt (or one thousandth of a picovolt)	a measure of the potential energy of a unit charge at a given point in a circuit relative to a reference point (ground)