/ Dictionary / Index P phototoxin: Meaning and Definition of Find definitions for: pho•to•tox•in Pronunciation: (fō'tu-tok"sin), [key] — n. a plant toxin causing an allergic reaction when touched or eaten by a susceptible person or animal subsequently exposed to sunlight. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. phototopography phototransistor Related Content Daily Word Quiz: crutiny Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language