mill vs coffee grinder

mill and coffee grinder both are nouns.

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

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

mill (noun)	coffee grinder (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 grinder (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