Halloween is a holiday celebrated on the night of October 31, usually by children dressing in costumes and going door-to-door collecting candy. It is celebrated in much of the Western world, though most commonly in the United States, the United Kingdom, the Republic of Ireland, Canada and sometimes in Australia and New Zealand. Irish, Scots and other immigrants brought older versions of the tradition to North America in the 19th century. Most other Western countries have embraced Halloween as a part of American pop culture in the late 20th century.
The term "Halloween" derives from Hallowe'en, an old contraction, still retained in Scotland and some parts of Canada, of "All Hallow's Eve," so called as it is the day before All Saints day (observed by some Christians, including Roman Catholics), which used to be called "All Hallows," derived from All Hallowed Souls.
In Ireland, the name was Hallow Eve and this name is still used by some older people. Halloween was formerly also sometimes called All Saints' Eve. The holiday was a day of religious festivities in various northern European pagan traditions, until it was appropriated by Christian missionaries (along with Christmas and Easter, two other traditional northern European pagan holidays) and given a Christian reinterpretation.
In Mexico, All Saint's Day, following Halloween, is the Day of the Dead.
Halloween is also called "Pooky Night" in some parts of Ireland, presumably named after the puca, a mischievous spirit