from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A hinged or sliding door in a floor, roof, or ceiling.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A hinged or sliding door set into a floor or ceiling.
- n. Such a trap set into the floor of a stage to allow fast exits and entrances.
- n. A secret method of obtaining access to a program or online system; a backdoor.
- n. The special information that permits the inverse of a trapdoor function to be easily computed.
from the GNU version of the Collaborative International Dictionary of English
- n. A lifting or sliding door covering an opening in a roof or floor.
- n. A door in a level for regulating the ventilating current; -- called also weather door.
from The Century Dictionary and Cyclopedia
- n. In mining, a door designed to direct air-currents in ventilating systems, or to prevent, surface wind from deranging the normal direction of air-currents.
- n. A door in a floor or roof which when shut is flush, or nearly so, with what surrounds it.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a hinged or sliding door in a floor or ceiling
trap + door (Wiktionary)