/ Dictionary / Index P phototaxis: Meaning and Definition of Find definitions for: pho•to•tax•is Pronunciation: (fō"tu-tak'sis), [key] — n. Biol. movement of an organism toward or away from a source of light. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. photosynthesis phototelegraphy 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