restraint vs device

restraint and device both are nouns.

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

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

restraint (noun)	device (noun)
the act of controlling by restraining someone or something	any clever maneuver
a device that retards something's motion	an instrumentality invented for a particular purpose
discipline in personal and social activities	an emblematic design (especially in heraldry)
lack of ornamentation	any ornamental pattern or design (as in embroidery)
a rule or condition that limits freedom	something in an artistic work designed to achieve a particular effect
the state of being physically constrained