traffic light

American  

noun

1. a set of electrically operated signal lights used to direct or control traffic at intersections.

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traffic light British  

noun

1. one of a set of coloured lights placed at crossroads, junctions, etc, to control the flow of traffic. A red light indicates that traffic must stop and a green light that it may go: usually an amber warning light is added between the red and the green

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Etymology

Origin of traffic light

First recorded in 1925–30

Example Sentences

Seven months ago, a self-driving Waymo made an illegal U-turn at a traffic light right in front of police officers in San Bruno.

From Los Angeles Times • May 1, 2026

Drivers in England will be able to see how local authorities are tackling roads riddled with potholes via a new mapping tool and traffic light rating system.

From BBC • Jan. 10, 2026

But for many of us, there can be some surprising signals—like a flashing yellow traffic light inside your head.

From The Wall Street Journal • Nov. 19, 2025

Last month, police officers in San Bruno, CA, observed a self-driving Waymo make an illegal U-turn at a traffic light.

From Los Angeles Times • Oct. 21, 2025

I continued to stare at the traffic light, which glowed red.

From "The Poisonwood Bible" by Barbara Kingsolver

Related Words

• red light
• stoplight
• traffic control
• yellow light