Source : Webster's Revised Unabridged Dictionary (1913)

Nux vomica \Nux` vom"i*ca\ [NL., fr. L. nux ? nut + vomere to
   vomit.]
   The seed of {Strychnos Nuxvomica}, a tree which abounds on
   the Malabar and Coromandel coasts of the East Indies. From
   this seed the deadly poisons known as strychnine and brucine
   are obtained. The seeds are sometimes called Quaker buttons.

Source : WordNet®

nux vomica
     n : a medicine made from the seeds of an Asiatic tree; contains
         strychnine and brucine; formerly used as a stimulant