United Mexican States vs Yucatan

United Mexican States and Yucatan both are nouns.

Word	Noun	Adjective	Verb	Adverb
United Mexican States	Yes	No	No	No
Yucatan	Yes	No	No	No

United Mexican States (noun)	Yucatan (noun)
a republic in southern North America; became independent from Spain in 1810	a peninsula in Central America extending into the Gulf of Mexico between the Bay of Campeche and the Caribbean Sea
	a state of Mexico on the northern part of the Yucatan Peninsula