Scottish: habitational name from the lands of Sneddon in Paisley (Renfrewshire), from Snawdon in Garvald and Barra (East Lothian), or perhaps from Snawdon near Thirlestane in Lauderdale (Berwickshire). Whichever placename is involved in the surname is ultimately from Old English snāw ‘snow’ + dūn ‘hill’, like the famous Snowdon in Wales. Those in Scotland may be independent coinings and literal descriptions of hills on which snow tended to lie long, but Snowdoun or Snawdoun also belong to a group of Arthurian names, popular in Scotland in the later Middle Ages, and may have been applied as such in the names mentioned and also in the case of the lost Snadown by St. Andrews (Fife). Stirling was regarded as standing on the boundary of the ancient Scottish and British kingdoms, with strong associations with King Arthur, making it possible for King David II to claim to the chronicler Jean Froissart in 1365 that Stirling Castle was the Snowdon of King Arthur. It may be that the placename(s) supplying the surname allude to this potent mythology.