/ Dictionary / Index P photofission: Meaning and Definition of Find definitions for: pho•to•fis•sion Pronunciation: (fō"tu-fish'un, fō'tu-fish"-), [key] — n. Physics. nuclear fission induced by the absorption of a high-energy photon. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. photofinishing photoflash Related Content Daily Word Quiz: frugal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language