The Collaborative International Dictionary of English v.0.48:

Janitor \Jan"i*tor\, n. [L., fr. janua a door.]
   1. A door-keeper; a porter. [Archaic]
      [1913 Webster PJC]

   2. One who is employed to care for a public building, or a
      building occupied for offices, suites of rooms, etc.; a
      caretaker; -- the duties may include removal of trash,
      cleaning of the rooms and public areas, and minor repairs.
      [1913 Webster PJC] Janitress

WordNet (r) 3.0 (2006):

janitor
    n 1: someone employed to clean and maintain a building