Caribbean vs Caribbean Sea

Caribbean and Caribbean Sea both are nouns.

Word	Noun	Adjective	Verb	Adverb
Caribbean	Yes	No	No	No
Caribbean Sea	Yes	No	No	No

As nouns, Caribbean and Caribbean Sea are synonyms defined as:

Caribbean and Caribbean Sea: an arm of the Atlantic Ocean between North and South America; the origin of the Gulf stream

Caribbean (noun)	Caribbean Sea (noun)
region including the Caribbean Islands	an arm of the Atlantic Ocean between North and South America; the origin of the Gulf stream
an arm of the Atlantic Ocean between North and South America; the origin of the Gulf stream