factory worker vs mill-hand

factory worker and mill-hand both are nouns.

Word	Noun	Adjective	Verb	Adverb
factory worker	Yes	No	No	No
mill-hand	Yes	No	No	No

As nouns, factory worker and mill-hand are synonyms defined as:

factory worker (noun)	mill-hand (noun)
a workman in a mill or factory	a workman in a mill or factory