shortening vs reduction

shortening and reduction both are nouns.

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

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

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

shortening (noun)	reduction (noun)
act of decreasing in length	the act of decreasing or reducing something
fat such as butter or lard used in baked goods	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