\U"pas\, n. [Malay p?hn-?pas; p?hn a tree + ?pas poison.]
1. (Bot.) A tree ({Antiaris toxicaria}) of the Breadfruit
   family, common in the forests of Java and the neighboring
   islands. Its secretions are poisonous, and it has been
   fabulously reported that the atmosphere about it is
   deleterious. Called also {bohun upas}.
2. A virulent poison used in Java and the adjacent islands
   for poisoning arrows. One kind, {upas antiar}, is, derived
   from upas tree ({Antiaris toxicaria}). {Upas tieute} is
   prepared from a climbing plant ({Strychnos Tieute}).