The word phototropism comes from the Greek roots:
• “photo-” (φῶς, φωτός) meaning “light”
• “tropism” (τροπή, tropē) meaning “a turn” or “a turning”
Thus, phototropism literally means “turning towards light.” It refers to the growth movement of plants in response to light direction, typically seen in stems bending toward a light source. The term was first recorded in scientific usage in the late 19th century.