miller vs milling machine

miller and milling machine both are nouns.

Word	Noun	Adjective	Verb	Adverb
miller	Yes	No	No	No
milling machine	Yes	No	No	No

As nouns, miller and milling machine are synonyms defined as:

miller and milling machine: machine tool in which metal that is secured to a carriage is fed against rotating cutters that shape it

miller (noun)	milling machine (noun)
any of various moths that have powdery wings	machine tool in which metal that is secured to a carriage is fed against rotating cutters that shape it
machine tool in which metal that is secured to a carriage is fed against rotating cutters that shape it
someone who works in a mill (especially a grain mill)