from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of or relating to the range of invisible radiation wavelengths from about 750 nanometers, just longer than red in the visible spectrum, to 1 millimeter, on the border of the microwave region.
- adj. Generating, using, or sensitive to infrared radiation.
- n. Infrared light or the infrared part of the spectrum.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. electromagnetic radiation of a wavelength longer than visible light, but shorter than microwave radiation, having a wavelength between 700 nm and 1 mm
- adj. Having the wavelength in the infrared.
from the GNU version of the Collaborative International Dictionary of English
- adj. 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.
- adj. relating to, using, or producing infrared radiation.
- adj. affected by infrared radiation.
from The Century Dictionary and Cyclopedia
- Below the red.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. having or employing wavelengths longer than light but shorter than radio waves; lying outside the visible spectrum at its red end
- n. the infrared region of the electromagnetic spectrum; electromagnetic wave frequencies below the visible range
- n. electromagnetic radiation with wavelengths longer than visible light but shorter than radio waves
Latin infra, below, + red (Wiktionary)