power unit vs var

power unit and var both are nouns.

Word	Noun	Adjective	Verb	Adverb
power unit	Yes	No	No	No
var	Yes	No	No	No

As nouns, var is a hyponym of power unit; that is, var is a word with a more specific, narrower meaning than power unit:

power unit: a measure of electric power
var: a unit of electrical power in an AC circuit equal to the power dissipated when 1 volt produces a current of 1 ampere

Other hyponyms of power unit include abwatt, milliwatt, W, watt, kilowatt, kW, megawatt, H.P., horsepower, HP, volt-ampere, kilovolt-ampere.

power unit (noun)	var (noun)
a measure of electric power	a unit of electrical power in an AC circuit equal to the power dissipated when 1 volt produces a current of 1 ampere