Saint Vincent and the Grenadines vs St. Vincent

Saint Vincent and the Grenadines and St. Vincent both are nouns.

Word	Noun	Adjective	Verb	Adverb
Saint Vincent and the Grenadines	Yes	No	No	No
St. Vincent	Yes	No	No	No

Saint Vincent and the Grenadines (noun)	St. Vincent (noun)
an island country in the central Windward Islands; achieved independence from the United Kingdom in 1979	an island in the center of the Windward Islands; the largest of the islands comprising Saint Vincent and the Grenadines