The Collaborative International Dictionary of English v.0.48:

Tube \Tube\, v. t. [imp. & p. p. Tubed; p. pr. & vb. n.
   Tubing.]
   To furnish with a tube; as, to tube a well.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tubing \Tub"ing\, n.
   1. The act of making tubes.
      [1913 Webster]

   2. A series of tubes; tubes, collectively; a length or piece
      of a tube; material for tubes; as, leather tubing.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tubing
    n 1: conduit consisting of a long hollow object (usually
         cylindrical) used to hold and conduct objects or liquids or
         gases [syn: tube, tubing]