coulomb vs charge unit

coulomb and charge unit both are nouns.

Word	Noun	Adjective	Verb	Adverb
coulomb	Yes	No	No	No
charge unit	Yes	No	No	No

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

coulomb: a unit of electrical charge equal to the amount of charge transferred by a current of 1 ampere in 1 second
charge unit: a measure of the quantity of electricity (determined by the amount of an electric current and the time for which it flows)

Other hypernyms of coulomb include quantity unit.

coulomb (noun)	charge unit (noun)
a unit of electrical charge equal to the amount of charge transferred by a current of 1 ampere in 1 second	a measure of the quantity of electricity (determined by the amount of an electric current and the time for which it flows)