fire extinguisher vs device

fire extinguisher and device both are nouns.

Word	Noun	Adjective	Verb	Adverb
fire extinguisher	Yes	No	No	No
device	Yes	No	No	No

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

fire extinguisher (noun)	device (noun)
a manually operated device for extinguishing small fires	any clever maneuver
	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