king vs Ethelred I

king and Ethelred I both are nouns.

Word	Noun	Adjective	Verb	Adverb
king	Yes	No	No	No
Ethelred I	Yes	No	No	No

king (noun)	Ethelred I (noun)
(chess) the weakest but the most important piece	king of Wessex and Kent and elder brother of Alfred; Alfred joined Ethelred's battle against the invading Danes and succeeded him on his death (died in 871)
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