The most common meaning; refers to the red-yellow-green lights controlling road traffic.
The traffic light at the next intersection turned red.
Because the traffic signal is broken, a police officer is directing traffic.
signal device; semaphore
Broader meaning: any mechanical or electrical signaling apparatus, such as railway signals or industrial indicators. Less common than sense 1.
Railway signals are important devices that ensure train safety.
The traffic light changed from red to green.
Cyclists also have to obey the traffic lights.
The traffic light malfunctioned due to the typhoon, causing chaos at the intersection.