lowering vs reduction

lowering and reduction both are nouns.

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

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

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

lowering (noun)	reduction (noun)
the act of causing to become less	the act of decreasing or reducing something
the act of causing something to move to a lower level	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

lowering (adjective)	reduction (adjective)
darkened by clouds