infrared radiation
nounUK /ˌɪnfrəˈred ˌreɪdiˈeɪʃn/
US /ˌɪnfrəˈred ˌreɪdiˈeɪʃn/
Invisible light that feels warm, like the heat you feel from the sun or a fire.
The remote control sends infrared radiation to the TV to change the channel.
OTHER MEANINGS
2. A type of energy used in night-vision cameras to see in the dark.
The security camera uses infrared radiation to spot animals at night.
3. Heat given off by warm objects that can be detected by special devices.
The thermal camera showed the dog's body heat as bright infrared radiation.
4. Part of the light spectrum just beyond red that human eyes cannot see.
Scientists study infrared radiation to learn about distant stars.