Gila River vs Gila

Gila River and Gila both are nouns.

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

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

Gila River and Gila: a river that rises in western New Mexico and flows westward through southern Arizona to become a tributary of the Colorado River

Gila River (noun)	Gila (noun)
a river that rises in western New Mexico and flows westward through southern Arizona to become a tributary of the Colorado River	a river that rises in western New Mexico and flows westward through southern Arizona to become a tributary of the Colorado River