出典:Wiktionary
(This etymology is missing または incomplete. Please add to it, または discuss it at the 語源 scriptorium.) So called because the Gates of Hell supposedly opened up the night before Halloween, which would allow demons to wander towns and cause mischief. In some areas, the name refers to the mischief of lifting residential gates off their hinges and either exchanging them with other people's gates, or placing them in awkward places such as suspended in trees.