convenience vs device

convenience and device both are nouns.

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

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

convenience (noun)	device (noun)
a device or control that is very useful for a particular job	any clever maneuver
a toilet that is available to the public	an instrumentality invented for a particular purpose
the quality of being useful and convenient	an emblematic design (especially in heraldry)
the state of being suitable or opportune	any ornamental pattern or design (as in embroidery)
	something in an artistic work designed to achieve a particular effect