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

Moby Thesaurus II by Grady Ward, 1.0:

41 Moby Thesaurus words for "janitor":
   air warden, attendant, caretaker, castellan, cerberus, char,
   charwoman, cleaner, cleaner-off, cleaner-up, cleaning lady,
   cleaning man, cleaning woman, concierge, conservator, curator,
   custodian, doorkeeper, doorman, forest ranger, game warden,
   gamekeeper, gatekeeper, governor, guardian, guardian angel,
   janitress, keeper, lifeguard, lifesaver, next friend, ostiary,
   porter, prochein ami, ranger, receptionist, shepherd, steward,
   usher, warden, warder