Source : Webster's Revised Unabridged Dictionary (1913)

Corridor \Cor"ri*dor\ (k?r"r?-d?r or -d?r), n. [F., fr. Itt.
   corridpore, or Sp. corredor; prop., a runner, hence, a
   running or long line, a gallery, fr. L. currere to run. See
   {Course}.]
   1. (Arch.) A gallery or passageway leading to several
      apartments of a house.

   2. (Fort.) The covered way lying round the whole compass of
      the fortifications of a place. [R.]

Source : WordNet®

corridor
     n : an enclosed passageway; rooms usually open onto it