reduction vs step-down

reduction and step-down both are nouns.

Word	Noun	Adjective	Verb	Adverb
reduction	Yes	No	No	No
step-down	Yes	No	No	No

As nouns, reduction and step-down are synonyms defined as:

Other synonyms of reduction include decrease, diminution.

reduction (noun)	step-down (noun)
the act of decreasing or reducing something	the act of decreasing or reducing something
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