1. [n]  electric underground railway
2. [n]  conduit consisting of a long hollow object (usually cylindrical) used to hold and conduct liquids or gases
3. [n]  electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope
4. [n]  (anatomy) any hollow cylindrical body structure
5. [n]  a hollow cylindrical shape
6. [v]  convey in a tube

1. \Tube\, n. (Elec. Railways)
   A tunnel for a tube railway; also (Colloq.), a tube railway.
   [Chiefly Eng.]
   

2. \Tube\, n. [L. tubus; akin to tuba a trumpet: cf F. tube.]
   1. A hollow cylinder, of any material, used for the
      conveyance of fluids, and for various other purposes; a
      pipe.
   2. A telescope. ``Glazed optic tube.'' --Milton.
   3. A vessel in animal bodies or plants, which conveys a fluid
      or other substance.
   4. (Bot.) The narrow, hollow part of a gamopetalous corolla.
   5. (Gun.) A priming tube, or friction primer. See under
      {Priming}, and {Friction}.
   6. (Steam Boilers) A small pipe forming part of the boiler,
      containing water and surrounded by flame or hot gases, or
      else surrounded by water and forming a flue for the gases
      to pass through.
   7. (Zo["o]l.)
      (a) A more or less cylindrical, and often spiral, case
          secreted or constructed by many annelids, crustaceans,
          insects, and other animals, for protection or
          concealment. See Illust. of {Tubeworm}.
      (b) One of the siphons of a bivalve mollusk.
   {Capillary tube}, a tube of very fine bore. See {Capillary}.
   {Fire tube} (Steam Boilers), a tube which forms a flue.
   {Tube coral}. (Zo["o]l.) Same as {Tubipore}.
   {Tube foot} (Zo["o]l.), one of the ambulacral suckers of an
      echinoderm.
   {Tube plate}, or {Tube sheet} (Steam Boilers), a flue plate.
      See under {Flue}.
   {Tube pouch} (Mil.), a pouch containing priming tubes.
   {Tube spinner} (Zo["o]l.), any one of various species of
      spiders that construct tubelike webs. They belong to
      {Tegenaria}, {Agelena}, and allied genera.
   {Water tube} (Steam Boilers), a tube containing water and
      surrounded by flame or hot gases.
   

3. \Tube\, v. t. [imp. & p. p. {Tubed}; p. pr. & vb. n.
   {Tubing}.]
   To furnish with a tube; as, to tube a well.
   

1. A CRT terminal. Never used in the mainstream sense of TV; real hackers don't watch TV, except for Loony Toons, Rocky & Bullwinkle, Trek Classic, the Simpsons, and the occasional cheesy old swashbuckler movie.

2. electron tube.

3. (IBM) To send a copy of something to someone else's terminal. "Tube me that note."

[Jargon File]