the night of 31 October, the eve of All Saints' Day, often celebrated by children dressing up in frightening masks and costumes. Halloween is thought to be associated with the Celtic festival Samhain, when ghosts and spirits were believed to be abroad.
Samhain: festival marking the end of the harvest season and the beginning of winter or the "darker half" of the year. It is celebrated from sunset on 31 October to sunset on 1 November, which is nearly halfway between the autumn equinox and the winter solstice.
harvest: the gathering of crops.
equinox:the time when the sun crosses the plane of the earth's equator, making night and day ofapproximately equal length all over the earth and occurring about March 21