The word "Halloween" means the eve or evening before All Saints' Day (also called All Hallows' Day) celebrated on October 31. The term derives from "All Hallows' Evening," which was shortened to "Allhallowe'en" and then to "Halloween." It originated as a Christian holiday to mark the vigil of All Saints' Day, a time dedicated to remembering saints, martyrs, and the faithful departed. Halloween's deeper roots go back to the ancient Celtic festival of Samhain, celebrated as a time when the boundary between the living and the dead was thin, allowing spirits to return to Earth. As Christianity spread, the pagan Samhain was partly integrated into Christian traditions around remembering the dead. Over time, Halloween evolved from these religious observances to a largely secular celebration involving costumes, trick-or- treating, carved pumpkins (jack-o'-lanterns), and other customs symbolizing the supernatural and the macabre. In essence, Halloween means the "eve of All Hallows," a night historically linked to honoring ancestors and the dead, blending Christian and ancient Celtic traditions.