Arthur is of uncertain origin, usually explained as "bear" from the Celtic artos, though some scholars derive it from the Roman family name Artorius. The legendary King Arthur of the Round Table has made it a name of knights and chivalry since the Middle Ages, and it was a top 20 name in America in the early 1900s. Arthur has returned from number 316 in 2000 to the top 100 for the first time this century in 2025, ranking number 87.