peripheral vs peripheral device

peripheral and peripheral device both are nouns.

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

As nouns, peripheral and peripheral device are synonyms defined as:

peripheral and peripheral device: electronic equipment external to the circuit board that contains the CPU of a computer

Other synonyms of peripheral include computer peripheral.

peripheral (noun)	peripheral device (noun)
electronic equipment external to the circuit board that contains the CPU of a computer	electronic equipment external to the circuit board that contains the CPU of a computer

peripheral (adjective)	peripheral device (adjective)
on or near an edge or constituting an outer boundary; the outer area
related to the key issue but not of central importance