1. Aphototaxis (s) (noun), aphototaxes (pl) The absence of any response to a light stimulus by an organism that can move: The Aphototaxis of organisms is a condition that is characterized by their failure to react to light; neither moving toward the source of light (positive phototaxis) nor away from it (negative phototaxis).

2. Aphototaxis (s) (noun), aphototaxes (pl) The absence of any response to a light stimulus by an organism that can move: The Aphototaxis of organisms is a condition that is characterized by their failure to react to light; neither moving toward the source of light (positive phototaxis) nor away from it (negative phototaxis).