1.
traffic light; traffic signal
A device installed at intersections and pedestrian crossings that uses colored lights to control traffic flow.
2.
signal device; signaling equipment
More broadly, any mechanical or electronic device used to send signals, such as railway signals.
Refers specifically to the physical device, as opposed to 信号 which refers to the signal itself or is used colloquially for traffic lights in general. In everyday speech, most people say 信号 when talking about traffic lights, while 信号機 is the more precise, technical term for the actual equipment. Composed of 信号 (signal) + 機 (machine/device).
Common collocations
- 信号機の設置: installation of a traffic light
- 信号機の故障: traffic light malfunction
- 歩行者用信号機: pedestrian signal
- 押しボタン式信号機: push-button traffic light
- LED信号機: LED traffic light
Similar words
- 信号: signal; traffic light — the everyday word for traffic lights; 信号機 emphasizes the physical device
- 標識: sign; road sign — a fixed sign rather than a light-based signal
Cultural note
In Japan, the green traffic light is traditionally called 青 (blue) rather than 緑 (green), reflecting the broader Japanese color category where 青 historically encompassed both blue and green.