The Collaborative International Dictionary of English v.0.48:

Port \Port\, n. [F. porte, L. porta, akin to portus; cf. AS.
   porte, fr. L. porta. See Port a harbor, and cf. Porte.]
   1. A passageway; an opening or entrance to an inclosed place;
      a gate; a door; a portal. [Archaic]
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            Him I accuse
            The city ports by this hath entered.  --Shak.
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            Form their ivory port the cherubim
            Forth issuing.                        --Milton.
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   2. (Naut.) An opening in the side of a vessel; an embrasure
      through which cannon may be discharged; a porthole; also,
      the shutters which close such an opening.
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            Her ports being within sixteen inches of the water.
                                                  --Sir W.
                                                  Raleigh.
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   3. (Mach.) A passageway in a machine, through which a fluid,
      as steam, water, etc., may pass, as from a valve to the
      interior of the cylinder of a steam engine; an opening in
      a valve seat, or valve face.
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   Air port, Bridle port, etc. See under Air, Bridle,
      etc.

   Port bar (Naut.), a bar to secure the ports of a ship in a
      gale.

   Port lid (Naut.), a lid or hanging for closing the
      portholes of a vessel.

   Steam port, & Exhaust port (Steam Engine), the ports of
      the cylinder communicating with the valve or valves, for
      the entrance or exit of the steam, respectively.
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