sun gear vs geared wheel

sun gear and geared wheel both are nouns.

Word	Noun	Adjective	Verb	Adverb
sun gear	Yes	No	No	No
geared wheel	Yes	No	No	No

As nouns, geared wheel is a hypernym of sun gear; that is, geared wheel is a word with a broader meaning than sun gear:

sun gear: the central gear in an epicyclic train
geared wheel: a toothed wheel that engages another toothed mechanism in order to change the speed or direction of transmitted motion

Other hypernyms of sun gear include cogwheel, gear, gear wheel.

sun gear (noun)	geared wheel (noun)
the central gear in an epicyclic train	a toothed wheel that engages another toothed mechanism in order to change the speed or direction of transmitted motion