/ Dictionary / Index P photosynthesis: Meaning and Definition of Find definitions for: pho•to•syn•the•sis Pronunciation: (fō"tu-sin'thu-sis), [key] — n. Biol., Biochem. (esp. in plants) the synthesis of complex organic materials, esp. carbohydrates, from carbon dioxide, water, and inorganic salts, using sunlight as the source of energy and with the aid of chlorophyll and associated pigments. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: photosynthesis (Thesaurus) photosynthate phototaxis Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language