magnet vs device

magnet and device both are nouns.

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

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

magnet (noun)	device (noun)
(physics) a device that attracts iron and produces a magnetic field	any clever maneuver
a characteristic that provides pleasure and attracts	an instrumentality invented for a particular purpose
	an emblematic design (especially in heraldry)
	any ornamental pattern or design (as in embroidery)
	something in an artistic work designed to achieve a particular effect