'Infra-red' definitions:

Definition of 'Infra-red'

From: GCIDE
  • 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]