The Collaborative International Dictionary of English v.0.48:

Flange \Flange\ (fl[a^]nj), n. [Prov. E. flange to project,
   flanch a projection. See Flanch, Flank.]
   1. An external or internal rib, or rim, for strength, as the
      flange of an iron beam; or for a guide, as the flange of a
      car wheel (see Car wheel.); or for attachment to another
      object, as the flange on the end of a pipe, steam
      cylinder, etc. --Knight.
      [1913 Webster]

   2. A plate or ring to form a rim at the end of a pipe when
      fastened to the pipe.
      [1913 Webster]

   Blind flange, a plate for covering or closing the end of a
      pipe.

   Flange joint, a joint, as that of pipes, where the
      connecting pieces have flanges by which the parts are
      bolted together. --Knight.

   Flange rail, a rail with a flange on one side, to keep
      wheels, etc. from running off.

   Flange turning, the process of forming a flange on a
      wrought iron plate by bending and hammering it when hot.
      [1913 Webster]