Source : Webster's Revised Unabridged Dictionary (1913)

Upas \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}).

Antiar \An"ti*ar\, n. [Jav. antjar.]
   A Virulent poison prepared in Java from the gum resin of one
   species of the upas tree ({Antiaris toxicaria}).