The name Halloween (sometimes spelled Hallowe'en) is a contraction of "All Hallows Even." The word hallow, which means "to make holy" or "to revere as holy," was once also used as a noun to mean "holy place" or "holy person" -- e.g., a saint. Thus, in Catholic liturgy October 31 is designated All Hallows Eve because it's the day before the Festival of All Saints, or All Saints
Day. The ancient Celts of Ireland and Scotland observed an annual harvest festival on November 1 known as Samhain (pronounced sow'-en or sow'-een), which marked the end of summer and was thought to be the time when the souls of those who had perished during the year journeyed to the "otherworld.When the peoples of the British Isles became Christianized during the early Middle Ages these customs and beliefs were transformed, though not abandoned. The Church designated the first and second of November All Saints Day (or All Hallows Day) and All Souls Day respectively When the peoples of the British Isles became Christianized during the early Middle Ages these customs and beliefs were transformed, though not abandoned. The Church designated the first and second of November All Saints Day (or All Hallows Day) and All Soul Day respectively .
According to legend, the jack o'lantern was named after a reprobate Irishman called Stingy Jack who tricked the Devil into promising he wouldn't go to hell for his sins. When Jack died he learned he was barred from heaven, so he went down to the gates of hell after all to beg for a final resting place. Wouldn't you know it, the Devil kept his promise, dooming Jack to wander the earth for all eternity with only an ember of hellfire of to light his way. Thenceforth he was known as Jack O'Lantern.
Trick-or-treating, is for children (and sometimes teens) on Halloween in which they proceed from house to house in costumes, asking for treats such as confectionery with the question, "Trick or treat?" The "trick" part of "trick or treat" is an idle threat to play a trick on the homeowners or their property if no treat is given.