far-infrared radiation

[ fahr-in-fruh-red ]

noun

1. the longer wavelengths of electromagnetic radiation in the infrared region of the spectrum, beyond the red end of the visible spectrum, from 50 to 1000 micrometers. : FIR

far-infrared radiation

/ fär′ĭn′frə-rĕd′ /

1. Infrared electromagnetic radiation of very long wavelengths, in the range of 2–50 microns. It is used in medicine to provide a penetrating heat to the body.
2. Also called far-red radiation