depreciation vs diminution

depreciation and diminution both are nouns.

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

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

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

depreciation (noun)	diminution (noun)
a decrease in price or value	the act of decreasing or reducing something
a communication that belittles somebody or something	the statement of a theme in notes of lesser duration (usually half the length of the original)
decrease in value of an asset due to obsolescence or use	change toward something smaller or lower