# trapdoor

> English word · Noun · IPA /ˈtræpdɔː/ · frequency rank #53,919

## Definitions
1. A hinged or sliding door set into a floor or ceiling.
2. Such a trap set into the floor of a stage to allow fast exits and entrances.
3. A secret method of obtaining access to a program or online system; a backdoor.
4. The special information that permits the inverse of a trapdoor function to be easily computed.
5. A door in a level for regulating the ventilating current; a weather door.

## Etymology
From trap + door.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/trapdoor