storage vs cold storage

storage and cold storage both are nouns.

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

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

Other hyponyms of storage include stowage, stowing, tankage.

storage (noun)	cold storage (noun)
the commercial enterprise of storing goods and materials	refrigerated storage for preservation
the act of storing something	in a state of abeyance or postponement
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