Took the reins is an idiom that means to take control or assume responsibility. The crossword solution for this term is LED, which stands for Light Emitting Diode. LEDs are a type of semiconductor device that emits light when an electric current passes through it. LEDs are used in many applications, such as lighting, displays, and indicators. They are also used in automotive headlights, traffic signals, and other signaling devices. By using LEDs, people can take the reins and take control of their environment.