San·ta Claus (sān'tə klôz') n. The personification of the spirit of Christmas, usually represented as a jolly fat old man with a white beard and a red suit, who brings gifts to good children on Christmas Eve.
[Probably alteration of Dutch Sinterklaas, from Middle Dutch Sinterclaes, St. Nicholas : sint, saint (from Middle Dutch, from Old French saint; see saint) + heer, lord; see mynheer + claes (short for Niclaes, Nicholas).]