memory device vs memory

memory device and memory both are nouns.

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

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

memory device (noun)	memory (noun)
a device that preserves information for retrieval	an electronic memory device
	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