Housatonic River vs Housatonic

Housatonic River and Housatonic both are nouns.

Word	Noun	Adjective	Verb	Adverb
Housatonic River	Yes	No	No	No
Housatonic	Yes	No	No	No

As nouns, Housatonic River and Housatonic are synonyms defined as:

Housatonic River and Housatonic: a river that rises in western Massachusetts and flows south through Connecticut to empty into Long Island Sound

Housatonic River (noun)	Housatonic (noun)
a river that rises in western Massachusetts and flows south through Connecticut to empty into Long Island Sound	a river that rises in western Massachusetts and flows south through Connecticut to empty into Long Island Sound