The Collaborative International Dictionary of English v.0.48:

Tubular \Tu"bu*lar\, a. [L. tubulus, dim. of tubus a tube, or
   pipe. See Tube.]
   Having the form of a tube, or pipe; consisting of a pipe;
   fistular; as, a tubular snout; a tubular calyx. Also,
   containing, or provided with, tubes.
   [1913 Webster]

   Tubular boiler. See under Boiler.

   Tubular breathing (Med.), a variety of respiratory sound,
      heard on auscultation over the lungs in certain cases of
      disease, resembling that produced by the air passing
      through the trachea.

   Tubular bridge, a bridge in the form of a hollow trunk or
      tube, made of iron plates riveted together, as the
      Victoria bridge over the St. Lawrence, at Montreal,
      Canada, and the Britannia bridge over the Menai Straits.


   Tubular girder, a plate girder having two or more vertical
      webs with a space between them.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tubular
    adj 1: constituting a tube; having hollow tubes (as for the
           passage of fluids) [syn: tubular, cannular,
           tubelike, tube-shaped, vasiform]