What is "jib door"

Jib \Jib\ (j[i^]b), n. [Named from its shifting from side to side. See Jib, v. i.., Jibe.]

1. (Naut.) A triangular sail set upon a stay or halyard extending from the foremast or fore-topmast to the bowsprit or the jib boom. Large vessels often carry several jibs; as, inner jib; outer jib; flying jib; etc.

2. (Mach.) The projecting arm of a crane, from which the load is suspended.

3. One that jibs, or balks; a jibber.

4. A stationary condition; a standstill.

   Jib boom (Naut.), a spar or boom which serves as an extension of the bowsprit. It is sometimes extended by another spar called the flying jib boom. [Written also gib boom.]

   Jib crane (Mach.), a crane having a horizontal jib on which a trolley moves, bearing the load.

   Jib door (Arch.), a door made flush with the wall, without dressings or moldings; a disguised door.

   Jib header (Naut.), a gaff-topsail, shaped like a jib; a jib-headed topsail.

   Jib topsail (Naut.), a small jib set above and outside of all the other jibs.

   The cut of one's jib, one's outward appearance. [Colloq.]
   --Sir W. Scott.