"Hallow" means saint. All Saints' Day, November 1, was formally called "Hallowmas" or "All Hallows." "Eve" means the day before. "Hallows' Eve," which became "Hallowe'en" in Scottish usage, is therefore the day before All Saints' Day, i.e. October 31. | "Hallow" means saint. All Saints' Day, November 1, was formally called "Hallowmas" or "All Hallows." "Eve" means the day before. "Hallows' Eve," which became "Hallowe'en" in Scottish usage, is therefore the day before All Saints' Day, i.e. October 31. |