Several names are used for Halloween, reflecting its historical and cultural roots. The most common alternative names are All Hallows' Eve or Allhalloween: These are the original names from which "Halloween" is derived. It's the evening before the Christian feast of All Saints' Day, leading to its also being called All Saints' Eve.
Research suggests Halloween was originally spelled “Hallowe’en,” a contraction of “All Hallows Even.” The word "hallow" comes from the Old English word "hālig," meaning "holy" or "saint."