1.
traffic light; traffic signal
A device installed at intersections and pedestrian crossings that uses colored lights to control traffic flow.
信号機が赤になった。
The traffic light turned red.
あの交差点には信号機がない。
There is no traffic light at that intersection.
歩行者用の信号機が青に変わるまで待ってください。
Please wait until the pedestrian signal turns green.
2.
signal device; signaling equipment
More broadly, any mechanical or electronic device used to send signals, such as railway signals.
鉄道の信号機が故障した。
The railway signal device broke down.
船の信号機で位置を知らせる。
To communicate position using a ship's signaling device.
この区間では自動の信号機が列車の運行を管理している。
In this section, automatic signal devices manage train operations.
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.