Source : Webster's Revised Unabridged Dictionary (1913)

Rheic \Rhe"ic\, a. [NL. Rheum rhubarb, Gr. ??? See {Rhubarb}.]
   (Chem.)
   Pertaining to, or designating, an acid (commonly called
   chrysophanic acid) found in rhubarb ({Rheum}). [Obsoles.]

Rheum \Rhe"um\ (r[=e]"[u^]m), n. [NL., from L. Rha the river
   Volga, on the banks of which it grows. See {Rhubarb}.] (Bot.)
   A genus of plants. See {Rhubarb}.

Rheum \Rheum\ (r[udd]m), n. [OF. reume, rheume, F. rhume a
   cold,, L. rheuma rheum, from Gr. ???, fr. "rei^n to flow,
   akin to E. stream. See {Stream}, n., and cf. {Hemorrhoids}.]
   (Med.)
   A serous or mucous discharge, especially one from the eves or
   nose.

         I have a rheum in mine eyes too.         --Shak.

   {Salt rheum}. (Med.) See {Salt rheum}, in the Vocab.

Rhubarb \Rhu"barb\, n. [F. rhubarbe, OF. rubarbe, rheubarbe,
   reubarbare, reobarbe, LL. rheubarbarum for rheum barbarum,
   Gr. ??? (and ??) rhubarb, from the river Rha (the Volga) on
   whose banks it grew. Originally, therefore, it was the
   barbarian plant from the Rha. Cf. {Barbarous},
   {Rhaponticine}.]
   1. (Bot.) The name of several large perennial herbs of the
      genus {Rheum} and order {Polygonace[ae]}.

   2. The large and fleshy leafstalks of {Rheum Rhaponticum} and
      other species of the same genus. They are pleasantly acid,
      and are used in cookery. Called also {pieplant}.

   3. (Med.) The root of several species of {Rheum}, used much
      as a cathartic medicine.

   {Monk's rhubarb}. (Bot.) See under {Monk}.

   {Turkey rhubarb} (Med.), the roots of {Rheum Emodi}.

Source : WordNet®

rheum
     n 1: a watery discharge from the mucous membranes (especially
          from the eyes or nose)
     2: rhubarb [syn: {genus Rheum}]