expenditure vs burnup

expenditure and burnup both are nouns.

Word	Noun	Adjective	Verb	Adverb
expenditure	Yes	No	No	No
burnup	Yes	No	No	No

As nouns, burnup is a hyponym of expenditure; that is, burnup is a word with a more specific, narrower meaning than expenditure:

expenditure (noun)	burnup (noun)
the act of spending money for goods or services	the amount of fuel used up (as in a nuclear reactor)
the act of consuming something	a high-speed motorcycle race on a public road
money paid out; an amount spent