[1] : The Collaborative International Dictionary of English v.0.48

infrared radiation \in`frared" ra`dia"tion\, n. infra- +
   red. physics
   electromagnetic radiation having a wavelength of between 700
   nanometers and 1 millimeter.

   note: infrared radiation is that electromagnetic radiation
         lying between the visible spectrum and the longest
         microwaves. it may be absorbed by matter in a manner
         specific to the absorbing substance, causing increased
         vibration of molecules. the infrared absorption
         spectrum of a chemical compound is often very specific,
         and the infrared absorption spectrum is therefore used
         to help identify chemical substances. infrared
         radiation is used in certain communication devices,
         such as television remote controls and communication
         devices between computers or between computers and
         peripherals.
         pjc

[2] : WordNet (r) 2.0

infrared radiation
     n : electromagnetic radiation with wavelengths longer than
         visible light but shorter than radio waves syn: infrared,
          infrared light, infrared emission
see also:
infrared infrared light infrared emission 

Radiation >> R Words
Radiation, definition of term: Radiation
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Infrared >> I Words
Infrared, definition of term: Infrared
infrared_pag1.html

Infrared Light >> I Words
Infrared Light, definition of term: Infrared Light
infrared+light_pag1.html

Solar Radiation >> S Words
Solar Radiation, definition of term: Solar Radiation
solar+radiation_pag1.html

Beta Radiation >> B Words
Beta Radiation, definition of term: Beta Radiation
beta+radiation_pag1.html

Gamma Radiation >> G Words
Gamma Radiation, definition of term: Gamma Radiation
gamma+radiation_pag1.html

Alpha Radiation >> A Words
Alpha Radiation, definition of term: Alpha Radiation
alpha+radiation_pag1.html