mill vs coffee mill

mill and coffee mill both are nouns.

Word	Noun	Adjective	Verb	Adverb
mill	Yes	No	Yes	No
coffee mill	Yes	No	No	No

As nouns, coffee mill is a hyponym of mill; that is, coffee mill is a word with a more specific, narrower meaning than mill:

mill (noun)	coffee mill (noun)
the act of grinding to a powder or dust	a mill that grinds roasted coffee beans
machinery that processes materials by grinding or crushing
a plant consisting of one or more buildings with facilities for manufacturing

mill (verb)	coffee mill (verb)
grind with a mill
produce a ridge around the edge of
roll out (metal) with a rolling machine
move about in a confused manner