/ Dictionary / Index P photoautotroph: Meaning and Definition of Find definitions for: pho•to•au•to•troph Pronunciation: (fō"tō-ô'tu-trof", -trōf"), [key] — n. Biol. any organism that derives its energy for food synthesis from light and is capable of using carbon dioxide as its principal source of carbon. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. photoanalyst photobiology Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language