storage vs tankage

storage and tankage both are nouns.

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

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

Other hyponyms of storage include cold storage, stowage, stowing.

storage (noun)	tankage (noun)
the commercial enterprise of storing goods and materials	the act of storing in tanks
the act of storing something	the charge for storing something in tanks
depositing in a warehouse	the quantity contained in (or the capacity of) a tank or tanks
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