U.S. vs Yukon River

U.S. and Yukon River both are nouns.

Word	Noun	Adjective	Verb	Adverb
U.S.	Yes	No	No	No
Yukon River	Yes	No	No	No

U.S. (noun)	Yukon River (noun)
the executive and legislative and judicial branches of the federal government of the United States	a North American river that flows westward from the Yukon Territory through central Alaska to the Bering Sea
North American republic containing 50 states - 48 conterminous states in North America plus Alaska in northwest North America and the Hawaiian Islands in the Pacific Ocean; achieved independence in 1776