a signal used to direct or control traffic; chiefly spec. (each of) a set of lights (usually red, amber, and green) used for automatic control of…

Frequently in plural. (Each of) a set of lights (usually red, amber, and green) used for automatic control of road traffic, esp. at junctions and…

Any of various devices (now esp. a set of coloured lights) situated on or adjacent to a road, junction, etc., and used to control or direct the…

A source of illumination. A traffic light.

An automatic traffic light. Also more fully traffic robot. Now South African.