roller vs sprocket

roller and sprocket both are nouns.

Word	Noun	Adjective	Verb	Adverb
roller	Yes	No	No	No
sprocket	Yes	No	No	No

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

Other hyponyms of roller include garden roller, paint roller, platen, trundle.

roller (noun)	sprocket (noun)
a grounder that rolls along the infield	thin wheel with teeth that engage with a chain
Old World bird that tumbles or rolls in flight; related to kingfishers	tooth on the rim of gear wheel
pigeon that executes backward somersaults in flight or on the ground	roller that has teeth on the rims to pull film or paper through
a cylinder that revolves
a mechanical device consisting of a cylindrical tube around which the hair is wound to curl it
a small wheel without spokes (as on a roller skate)
a long heavy sea wave as it advances towards the shore