P0268200 (fō′tō-tăk′sĭs)n. The movement of an organism or a cell toward or away from a source of light.pho′to·tac′tic(-tăk′tĭk) adj.pho′to·tac′ti·cal·ly adv.
phototactically
(ˌfəʊtəʊˈtæktɪklɪ) adv (Biology) biology in a phototactic manner EncyclopediaSeePhototaxisMedicalSeephototaxis