Source : Webster's Revised Unabridged Dictionary (1913)

Tabes \Ta"bes\, n. [L., a wasting disease.] (Med.)
   Progressive emaciation of the body, accompained with hectic
   fever, with no well-marked logical symptoms.

   {Tabes dorsalis}[NL., tabes of the back], locomotor ataxia;
      -- sometimes called simply tabes.

   {Tabes mesenterica}[NL., mesenteric tabes], a wasting disease
      of childhood characterized by chronic inflammation of the
      lymphatic glands of the mesentery, attended with caseous
      degeneration.

Source : WordNet®

tabes
     n : wasting of the body during a chronic disease