(n.) The influence of light on the movements of low organisms, as various infusorians, the zoospores of certain algae, etc.; also, the tendency to follow definite directions of motion or assume definite positions under such influence. If the migration is toward the source of light, it is termed positive phototaxis; if away from the light, negative phototaxis.
PHOTOTAXY
Meaning of PHOTOTAXY in English
Webster's English dictionary. Английский словарь Webster. 2012