worm wheel vs cogwheel

worm wheel and cogwheel both are nouns.

Word	Noun	Adjective	Verb	Adverb
worm wheel	Yes	No	No	No
cogwheel	Yes	No	No	No

As nouns, cogwheel is a hypernym of worm wheel; that is, cogwheel is a word with a broader meaning than worm wheel:

worm wheel: gear with the thread of a worm
cogwheel: a toothed wheel that engages another toothed mechanism in order to change the speed or direction of transmitted motion

Other hypernyms of worm wheel include gear, gear wheel, geared wheel.

worm wheel (noun)	cogwheel (noun)
gear with the thread of a worm	a toothed wheel that engages another toothed mechanism in order to change the speed or direction of transmitted motion