“Halloween (or Hallowe’en) is an annual holiday observed on October 31, primarily in Ireland, Scotland, Canada and the United States. It has roots in the Celtic festival of Samhain and the Christian holiday All Saints’ Day, but is today largely a secular celebration.
Common Halloween activities include trick-or-treating, wearing costumes and attending costume parties, carving jack-o’-lanterns, ghost tours, bonfires, apple bobbing, visiting haunted attractions, committing pranks, telling ghost stories or other frightening tales, and watching horror films…
Origin of name
The word Halloween is first attested in the 16th century and represents a Scottish variant of the fuller All-Hallows-Even (“evening”), that is, the night before All Hallows Day. Although the phrase All Hallows is found in Old English (ealra hlgena mssedg, mass-day of all saints), All-Hallows-Even is itself not attested until 1556,” quoting Wikipedia.