winder vs bobbin

winder and bobbin both are nouns.

Word	Noun	Adjective	Verb	Adverb
winder	Yes	No	No	No
bobbin	Yes	No	No	No

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

winder: mechanical device around which something can be wound
bobbin: a winder around which thread or tape or film or other flexible materials can be wound

Other hyponyms of winder include reel, spool, reel.

winder (noun)	bobbin (noun)
mechanical device around which something can be wound	a winder around which thread or tape or film or other flexible materials can be wound
mechanical device used to wind another device that is driven by a spring (as a clock)
a worker who winds (e.g., a winch or clock or other mechanism)