northern vs Union

northern is not a noun while Union is a noun.

Word	Noun	Adjective	Verb	Adverb
northern	No	Yes	No	No
Union	Yes	Yes	No	No

northern (noun)	Union (noun)
	the United States (especially the northern states during the American Civil War)

northern (adjective)	Union (adjective)
situated in regions of the north	being of or having to do with the northern United States and those loyal to the Union during the American Civil War
in or characteristic of a region of the United States north of (approximately) the Mason-Dixon line
coming from the north; used especially of wind
oriented toward the north