from
The Collaborative International Dictionary of English v.0.48
Infrared \In`fra*red"\, Infra-red \In`fra-red"\, a. [Infra- +
red.]
1. (Physics) Lying outside the visible spectrum at its red
end; -- said of rays having a longer wavelength (and thus
less refrangible) than the extreme red rays, specifically
those electromagnetic waves having a wavelength of between
700 nanometers and 1 millimeter.
[Webster 1913 Suppl. +PJC]
2. relating to, using, or producing infrared radiation.
[PJC]
3. affected by infrared radiation; as, infrared detector;
infrared film.
[PJC]