The Collaborative International Dictionary of English v.0.48:

Cupping \Cup"ping\ (k?p"p?ng), n. (Med.)
   The operation of drawing blood to or from the surface of the
   person by forming a partial vacuum over the spot. Also,
   sometimes, a similar operation for drawing pus from an
   abscess.
   [1913 Webster]

   Cupping glass, a glass cup in which a partial vacuum is
      produced by heat, in the process of cupping.

   Dry cupping, the application of a cupping instrument
      without scarification, to draw blood to the surface,
      produce counter irritation, etc.

   Wet cupping, the operation of drawing blood by the
      application of a cupping instrument after scarification.
      [1913 Webster]