Source : Webster's Revised Unabridged Dictionary (1913)

Beriberi \Be`ri*be"ri\, n. [Singhalese beri weakness.]
   An acute disease occurring in India, characterized by
   multiple inflammatory changes in the nerves, producing great
   muscular debility, a painful rigidity of the limbs, and
   cachexy.

Source : WordNet®

beriberi
     n : avitaminosis caused by lack of thiamine (vitamin B1)