Source : Webster's Revised Unabridged Dictionary (1913)

Pleurisy \Pleu"ri*sy\, n. [F. pleur['e]sie, L. pleurisis,
   pleuritis, Gr pleyri^tis (sc. no`sos), fr. pleyra` rib,
   side.] (Med.)
   An inflammation of the pleura, usually accompanied with
   fever, pain, difficult respiration, and cough, and with
   exudation into the pleural cavity.

   {Pleurisy root}. (Bot.)
   (a) The large tuberous root of a kind of milkweed ({Asclepias
       tuberosa}) which is used as a remedy for pleuritic and
       other diseases.
   (b) The plant itself, which has deep orange-colored flowers;
       -- called also {butterfly weed}.

Source : WordNet®

butterfly weed
     n : erect perennial of eastern and southern United States having
         showy orange flowers [syn: {orange milkweed}, {chigger
         flower}, {chiggerflower}, {pleurisy root}, {tuber root},
         {Indian paintbrush}, {Asclepias tuberosa}]