The story
In the film The Wizard of Oz, Dorothy's family (though not Dorothy) flees through such a door to shelter in a cellar while a tornado passes.
Etymology from Wiktionary, CC BY-SA 4.0.
Dorothy door
Today it means: A single door, or one of a pair of doors, which (when closed) is not vertical but instead lies at an angle close to horizontal, which leads into a basement or cellar. Full definition →