retention vs storage

retention and storage both are nouns.

Word	Noun	Adjective	Verb	Adverb
retention	Yes	No	No	No
storage	Yes	No	No	No

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

Other hyponyms of retention include withholding.

retention (noun)	storage (noun)
the act of retaining something	the commercial enterprise of storing goods and materials
the power of retaining liquid	the act of storing something
the power of retaining and recalling past experience	depositing in a warehouse
	a depository for goods
	an electronic memory device
	(computer science) the process of storing information in a computer memory or on a magnetic tape or disk