Darius the Great vs king

Darius the Great and king both are nouns.

Word	Noun	Adjective	Verb	Adverb
Darius the Great	Yes	No	No	No
king	Yes	No	No	No

Darius the Great (noun)	king (noun)
king of Persia who expanded the Persian Empire and invaded Greece but was defeated at the battle of Marathon (550-486 BC)	(chess) the weakest but the most important piece
	one of the four playing cards in a deck bearing the picture of a king
	a checker that has been moved to the opponent's first row where it is promoted to a piece that is free to move either forward or backward
	a male sovereign; ruler of a kingdom
	a very wealthy or powerful businessman
	a male competitor who holds a preeminent position
	the husband or widower of a queen
	preeminence in a particular category or group or field