Translation guide
Infrared radiation is a type of electromagnetic radiation with wavelengths longer than visible light. In Japanese, it is most commonly referred to as 赤外線 (sekigaisen), which literally means 'red outside rays'. This term is used in both technical and everyday contexts.
赤外線
infrared radiation
The physical phenomenon of infrared radiation, used in science, technology, and everyday contexts.
The standard term for infrared radiation. Used in all contexts from physics to consumer electronics.
赤外線は目に見えません。
Infrared radiation is invisible to the eye.
このカメラは赤外線を感知します。
This camera detects infrared radiation.
A more technical term emphasizing the emission aspect. Common in physics and engineering.
赤外放射の波長は可視光より長い。
The wavelength of infrared radiation is longer than that of visible light.
Infrared as a type of light or rays, often in consumer products like heaters or remote controls.
Same as above; also used for 'infrared light' or 'infrared rays'.
リモコンは赤外線を使っています。
The remote control uses infrared light.
Infrared heater, a common appliance.
冬は赤外線ヒーターが暖かいです。
In winter, infrared heaters are warm.
In compound words, 赤外 (sekigai) is often used as a prefix meaning 'infrared', e.g., 赤外線カメラ (infrared camera), 赤外線通信 (infrared communication).