/ Dictionary / Index U upas: Meaning and Definition of Find definitions for: u•pas Pronunciation: (y'pus), [key] — n. the poisonous milky sap of a large tree, Antiaris toxicaria, of the mulberry family, native to tropical Asia, Africa, and the Philippine Islands, used for arrow poison. the tree itself. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Upanishad upaya Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language