noun
1. the infrared region of the electromagnetic spectrum
electromagnetic wave frequencies below the visible range
e.g. they could sense radiation in the infrared
Synonym: infrared frequency
2. electromagnetic radiation with wavelengths longer than visible light but shorter than radio waves
Synonym: infrared lightinfrared radiationinfrared emission
adj
1. having or employing wavelengths longer than light but shorter than radio waves
lying outside the visible spectrum at its red end
e.g. infrared radiation
infrared photography