depletion vs reduction

depletion and reduction both are nouns.

Word	Noun	Adjective	Verb	Adverb
depletion	Yes	No	No	No
reduction	Yes	No	No	No

As nouns, reduction is a hypernym of depletion; that is, reduction is a word with a broader meaning than depletion:

Other hypernyms of depletion include decrease, diminution, step-down.

depletion (noun)	reduction (noun)
the act of decreasing something markedly	the act of decreasing or reducing something
the state of being depleted	the act of reducing complexity
	any process in which electrons are added to an atom or ion (as by removing oxygen or adding hydrogen); always occurs accompanied by oxidation of the reducing agent