/ Dictionary / Index P photothermic: Meaning and Definition of Find definitions for: pho•to•ther•mic Pronunciation: (fō"tu-thûr'mik), [key] — adj. pertaining to the thermal effects of light. pertaining to or involving both light and heat. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. phototherapy phototonus Related Content Daily Word Quiz: pristine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language