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traffic light

American  

noun

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

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of traffic light

First recorded in 1925–30

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

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

Some call them a "traffic light system"; critics have likened them to Nando's spice cards.

From BBC • Nov. 11, 2025

Indian home minister Amit Shah said the blast occurred around 7 p.m. in a Hyundai i20 car at a traffic light near the Red Fort.

From The Wall Street Journal • Nov. 10, 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

A traffic light turned momentarily yellow and then red, and Shadow put his foot on the brake.

From "American Gods" by Neil Gaiman

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.