n. A traffic control signal, traditionally consisting of three lights colored green, yellow/amber and red meaning proceed, prepare to stop and stop respectively.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a red light on the rear of a motor vehicle that signals when the brakes are applied to slow or stop
n. a visual signal to control the flow of traffic at intersections
Word Usage
"A metric called the stoplight process red, yellow, green was set up to track whether actions agreed upon in Afghanistan and Iraq were being implemented or whether policy needed to be adjusted or changed."