Halloween or Hallowe'en (/ˌhæləˈwiːn, -oʊˈiːn, ˌhɑːl-/; a contraction of "All Hallows' Evening"),[6] also known as Allhalloween,[7] All Hallows' Eve,[8] or All Saints' Eve,[9] is a yearly celebration observed in a number of countries on 31 October, the eve of the Western Christian feast of All Hallows' Day. It initiates the triduum of Allhallowtide,[10] the time in the liturgical year
dedicated to remembering the dead, including saints (hallows), martyrs, and all the faithful departed believers.[11] Within Allhallowtide, the traditional focus of All Hallows' Eve revolves around the theme of using "humor and ridicule to confront the power of death."[12]
https://en.wikipedia.org/wiki/Halloween