n. The habit of bending from the sunlight; -- said of certain plants. [ 1913 Webster ]
n. (Bot.) A tendency of leaves or other organs of plants to have their dorsal surface faced towards the rays of light. [ 1913 Webster ]
n. [ Helio- + Gr. &unr_; to turn. ] (Bot.) The phenomenon of turning toward the light, seen in many leaves and flowers. [ 1913 Webster ]