Whitsun: [OE] Whitsun is etymologically ‘white Sunday’. The name comes from the ancient tradition of clothing newly baptized people in white on the feast of Pentecost. The abbreviated form Whit began to be used with other days of the week (such as Whit Monday) in the 16th century, but its broader modern usage (as in Whit week, Whit bank holiday, etc) did not emerge until the end of the 19th century. => sunday, white