1. a hinged or sliding door in a floor or ceiling
WordNet (r) 3.0 (2006):
n 1: a hinged or sliding door in a floor or ceiling
Moby Thesaurus II by Grady Ward, 1.0:
34 Moby Thesaurus words for "trap door":
French door, archway, back door, barway, bulkhead,
carriage entrance, cellar door, cellarway, door, doorjamb,
doorpost, doorway, front door, gate, gatepost, gateway, hatch,
hatchway, lintel, porch, portal, porte cochere, postern,
propylaeum, pylon, scuttle, side door, stile, storm door,
threshold, tollgate, trap, turnpike, turnstile
The Jargon File (version 4.4.7, 29 Dec 2003):
1. Syn. back door ? a Bad Thing.
2. [techspeak] A trap-door function is one which is easy to compute but
very difficult to compute the inverse of. Such functions are Good Things
with important applications in cryptography, specifically in the
construction of public-key cryptosystems.
The Free On-line Dictionary of Computing (30 December 2018):
Or "trapdoor" 1. back door.
2. trap-door function