Colorado River vs Colorado

Colorado River and Colorado both are nouns.

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

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

Colorado River and Colorado: an important river in the southwestern United States; rises in the Rocky Mountains of northern Colorado and flows southwest through Utah into Arizona (where it flows through the Grand Canyon) and then southward through the southern tip of Nevada, then forming the border between California and Arizona and finally into Mexico where it empties into the Gulf of California; the main source of water in the southwestern United States

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

Colorado River and Colorado: a river in Texas; flows southeast into the Gulf of Mexico

Colorado River (noun)	Colorado (noun)
an important river in the southwestern United States; rises in the Rocky Mountains of northern Colorado and flows southwest through Utah into Arizona (where it flows through the Grand Canyon) and then southward through the southern tip of Nevada, then forming the border between California and Arizona and finally into Mexico where it empties into the Gulf of California; the main source of water in the southwestern United States	a state in west central United States in the Rocky Mountains
a river in Texas; flows southeast into the Gulf of Mexico	an important river in the southwestern United States; rises in the Rocky Mountains of northern Colorado and flows southwest through Utah into Arizona (where it flows through the Grand Canyon) and then southward through the southern tip of Nevada, then forming the border between California and Arizona and finally into Mexico where it empties into the Gulf of California; the main source of water in the southwestern United States
	a river in Texas; flows southeast into the Gulf of Mexico