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]