discount vs diminution

discount and diminution both are nouns.

Word	Noun	Adjective	Verb	Adverb
discount	Yes	No	Yes	No
diminution	Yes	No	No	No

As nouns, diminution is a hypernym of discount; that is, diminution is a word with a broader meaning than discount:

Other hypernyms of discount include decrease, reduction, step-down.

discount (noun)	diminution (noun)
the act of reducing the selling price of merchandise	the act of decreasing or reducing something
an amount or percentage deducted	the statement of a theme in notes of lesser duration (usually half the length of the original)
interest on an annual basis deducted in advance on a loan	change toward something smaller or lower
a refund of some fraction of the amount paid

discount (verb)	diminution (verb)
bar from attention or consideration
give a reduction in price on