Alpha Geminorum vs Castor

Alpha Geminorum and Castor both are nouns.

Word	Noun	Adjective	Verb	Adverb
Alpha Geminorum	Yes	No	No	No
Castor	Yes	No	No	No

As nouns, Alpha Geminorum and Castor are synonyms defined as:

Alpha Geminorum and Castor: a multiple star with 6 components; second brightest in Gemini; close to Pollux

Alpha Geminorum (noun)	Castor (noun)
a multiple star with 6 components; second brightest in Gemini; close to Pollux	type genus of the Castoridae: beavers
	a multiple star with 6 components; second brightest in Gemini; close to Pollux