Trapdoor
Pronunciation : Trap"door`
Part of Speech : n.
Definition : 1. (Arch.)
Defn: A lifting or sliding door covering an opening in a roof or floor.
2. (Mining)
Defn: A door in a level for regulating the ventilating current; -- called also weather door. Raymond. Trapdoor spider (Zo?l.), any one of several species of large spiders which make a nest consisting of a vertical hole in the earth, lined with a hinged lid, like a trapdoor. Most of the species belong to the genus Cteniza, as the California species (C. Californica).
Source : Webster's Unabridged Dictionary, 1913