Upper Carboniferous period vs Pennsylvanian

Upper Carboniferous period and Pennsylvanian both are nouns.

Word	Noun	Adjective	Verb	Adverb
Upper Carboniferous period	Yes	No	No	No
Pennsylvanian	Yes	No	No	No

As nouns, Upper Carboniferous period and Pennsylvanian are synonyms defined as:

Upper Carboniferous period and Pennsylvanian: the period from 310 million to 280 million years ago; characterized by warm climate and swampy land

Other synonyms of Upper Carboniferous period include Pennsylvanian period, Upper Carboniferous.

Upper Carboniferous period (noun)	Pennsylvanian (noun)
the period from 310 million to 280 million years ago; characterized by warm climate and swampy land	a native or resident of Pennsylvania
	the period from 310 million to 280 million years ago; characterized by warm climate and swampy land