/ Dictionary / Index P photodegradable: Meaning and Definition of Find definitions for: pho•to•de•grad•a•ble Pronunciation: (fō"tō-di-grā'du-bul), [key] — adj. (of a substance) capable of being broken down by light. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. photodecomposition photodetector 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