decrement vs shrinkage

decrement and shrinkage both are nouns.

Word	Noun	Adjective	Verb	Adverb
decrement	Yes	No	No	No
shrinkage	Yes	No	No	No

As nouns, shrinkage is a hyponym of decrement; that is, shrinkage is a word with a more specific, narrower meaning than decrement:

Other hyponyms of decrement include dip, drop, fall, free fall.

decrement (noun)	shrinkage (noun)
the amount by which something decreases	the act of stealing goods that are on display in a store
a process of becoming smaller or shorter	the amount by which something shrinks
	process or result of becoming less or smaller