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.

Source: Webster's Revised Unabridged Dictionary (1913)