Alternative spelling of doomsday device

A hypothetical weapon (often a bomb) programmed to automatically be used in response to certain attacks, usually with very dire consequences (such as the annihilation of the world).

A door that is reminiscent of the looks and styles of the original carriage house doors. / A door on a railway carriage.

doorjamb

(idiomatic) Dying, close to death.

present participle of knock on heaven's door

A door that rotates around a central pivot. / (figuratively) A system or institution in which people exit and immediately reenter.

plural of revolving door

Alternative form of doornail

An opening through which the ash is removed from a fireplace.