WhitsundayyoudaoicibaDictYouDict[Whitsunday 词源字典]
"Pentecost," late Old English Hwita Sunnandæg "white Sunday" (see white (adj.)); possibly so called from the white baptismal robes worn by newly baptized Christians on this day. Related: Whitsuntide.[Whitsunday etymology, Whitsunday origin, 英语词源]