Arthur vs President of the United States

Arthur and President of the United States both are nouns.

Word	Noun	Adjective	Verb	Adverb
Arthur	Yes	No	No	No
President of the United States	Yes	No	No	No

Arthur (noun)	President of the United States (noun)
a legendary king of the Britons (possibly based on a historical figure in the 6th century but the story has been retold too many times to be sure); said to have led the Knights of the Round Table at Camelot	the office of the United States head of state
elected vice president and became 21st President of the United States when Garfield was assassinated (1830-1886)	the person who holds the office of head of state of the United States government