Stoplight

Part of speech: noun

Definitions

1. A signaling apparatus utilized at road intersections to control the movement of traffic through distinct colored lights indicating when to stop or go
2. An essential device for managing vehicular and pedestrian traffic flow by displaying alternating red, yellow, and green lights at crossings
3. A device positioned at intersections that uses red, yellow, and green lights to regulate vehicle and pedestrian movement

Etymology: "Stoplight" is about as transparent as compounds get: "stop" paired with "light," meaning a light that tells drivers to halt. The sense is literal, with no metaphor or change in meaning to unpack. The first element is the everyday verb "stop," and "light" here means a signal lamp, the same sense that gives us "traffic light" and "headlight." The compound's pattern is also what makes it easy to read. English often forms nouns by placing a verb or action word before a noun that names the thing performing the function, as in "pushbutton" or "dashboard." The result is a name that describes the device by its job, which is why a traffic signal that calls for stopping ended up named for that instruction.

Synonyms: traffic light, signal