/hwit"sun"day, -dee, wit"-; hwit"seuhn day', wit"-/ , n.
the seventh Sunday after Easter, celebrated as a festival in commemoration of the descent of the Holy Spirit on the day of Pentecost.
[ bef. 1100; ME whitsonenday, OE Hwita Sunnandaeg white Sunday; prob. so called because the newly baptized wore white robes on that day ]