/ Dictionary / Index P photodecomposition: Meaning and Definition of Find definitions for: pho•to•de•com•po•si•tion Pronunciation: (fō"tō-dē"kom-pu-zish'un), [key] — n. Chem. the breaking down of molecules by radiant energy. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. photocurrent photodegradable Related Content Daily Word Quiz: feline Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language