windmill vs milling machinery

windmill and milling machinery both are nouns.

Word	Noun	Adjective	Verb	Adverb
windmill	Yes	No	No	No
milling machinery	Yes	No	No	No

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

windmill: a mill that is powered by the wind
milling machinery: machinery that processes materials by grinding or crushing

Other hypernyms of windmill include grinder, mill.

windmill (noun)	milling machinery (noun)
generator that extracts usable energy from winds	machinery that processes materials by grinding or crushing
a mill that is powered by the wind