Scottish, Irish, Welsh, English, and French: from the ancient Celtic personal name Arthur. In many cases it is a shortened form of Scottish or Irish McArthur, the patronymic Mac- often being dropped in the 17th, 18th, and 19th centuries under English influence. The personal name is most probably from an old Celtic word meaning ‘bear’. Compare Gaelic art, Welsh arth, both of which mean ‘bear’. It has been in regular use as a personal name in Britain since the early Middle Ages, owing its popularity in large part to the legendary exploits of King Arthur and the Knights of the Round Table, which gave rise to a prolific literature in Welsh, French, English, German, and other European languages.