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

Black boxes monitor driving habits and can provide a weekly rating graded using a traffic light colour scheme.

From BBC • May 14, 2026

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

The trust operated a traffic light system on patient files to indicate their level of need and the risk they posed to themselves or others.

From BBC • Nov. 9, 2025

And when you are coming up to a traffic light, you want to keep some momentum, if you can.

From The Wall Street Journal • Oct. 26, 2025

When I open my eyes, we’re stopped at a traffic light and she’s looking at me with this admiring-ish grin on her face.

From "Odd One Out" by Nic Stone

Related Words

• red light
• stoplight
• traffic control
• yellow light