spur gear vs spur wheel

spur gear and spur wheel both are nouns.

Word	Noun	Adjective	Verb	Adverb
spur gear	Yes	No	No	No
spur wheel	Yes	No	No	No

As nouns, spur gear and spur wheel are synonyms defined as:

spur gear (noun)	spur wheel (noun)
gear wheels that mesh in the same plane	gear wheels that mesh in the same plane