memory vs memory device

memory and memory device both are nouns.

Word	Noun	Adjective	Verb	Adverb
memory	Yes	No	No	No
memory device	Yes	No	No	No

As nouns, memory device is a hypernym of memory; that is, memory device is a word with a broader meaning than memory:

Other hypernyms of memory include computer hardware, hardware, storage device.

memory (noun)	memory device (noun)
an electronic memory device	a device that preserves information for retrieval
the power of retaining and recalling past experience
the cognitive processes whereby past experience is remembered
something that is remembered
the area of cognitive psychology that studies memory processes