Trapdoor

A trapdoor or hatch is a sliding or hinged door that is flush with the surface of a floor, ceiling, or roof.

[3] The trapdoor has played a pivotal function in the operation of the gallows, cargo ships, trains,[4] booby traps,[5] and more recently theatre and films.

The edge of a trapdoor furthest from the hinge accelerates faster than gravity, so that the condemned does not hit the flaps but falls freely.

[8][9] The term trapdoor also refers to a plate in the entry vestibule of a passenger railcar that permits access to high-level platforms when lying flat against the floor of the car, and which can be flipped open to expose steps for accessing ground-level platforms.

Many American commuter railroads which operate the Comet railcars made by Bombardier have trapdoors to accommodate passengers boarding and alighting on both high-level and ground-level platforms.

A trapdoor to a bomb shelter from World War II
Deck hatch of the Omega , the last square-rigged sailing cargo ship
19th century Star trap from the Theatre Royal, Drury Lane , London, Now at the Victoria and Albert Museum