windmill vs generator

windmill and generator both are nouns.

Word	Noun	Adjective	Verb	Adverb
windmill	Yes	No	No	No
generator	Yes	No	No	No

As nouns, generator is a hypernym of windmill; that is, generator is a word with a broader meaning than windmill:

windmill: generator that extracts usable energy from winds
generator: engine that converts mechanical energy into electrical energy by electromagnetic induction

windmill (noun)	generator (noun)
generator that extracts usable energy from winds	engine that converts mechanical energy into electrical energy by electromagnetic induction
a mill that is powered by the wind	an apparatus that produces a vapor or gas
	an electronic device for producing a signal voltage
	someone who originates or causes or initiates something