Twin Falls vs Twin

Twin Falls and Twin both are nouns.

Word	Noun	Adjective	Verb	Adverb
Twin Falls	Yes	No	No	No
Twin	Yes	No	No	No

As nouns, Twin Falls and Twin are synonyms defined as:

Twin Falls (noun)	Twin (noun)
a town on the Snake River in south central Idaho near the Twin Falls	a waterfall in the Snake River in southern Idaho
a waterfall in the Snake River in southern Idaho	(astrology) a person who is born while the sun is in Gemini