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See also: infra-red



infra- +‎ red



infrared (countable and uncountable, plural infrareds)

  1. (uncountable) The electromagnetic radiation of a wavelength longer than visible light, but shorter than microwave radiation, having a wavelength between 700 nm and 1 mm.
    Hypernym: electromagnetic radiation
    • 1962, John Nelson Howard, Transmission of the Atmosphere in the Infrared: A Review, page 3:
      Collisions of these 'transparent' molecules with the molecules that do have absorption bands in the infrared can have a considerable influence on the intensities of the observed absorption bands.
  2. (countable) A specific wavelength in this range.
    • 1924, The American Review of Tuberculosis, page 110:
      Sonne has shown that by means of the luminous rays the temperature in the tissue may be raised to a higher degree than by the use of the infrareds.
    • 2009, Alexander Grankov, Microwave Radiation of the Ocean-Atmosphere: Boundary Heat and Dynamic Interaction:
      Exposure of spectral pieces at centimeters, millimeters, and infrareds, which provide a top steadiness of the dependence "MCW radiation vs. parameter Δt" and its interannual (seasonal) dynamics.
  3. (countable) A device that emits infrared radiation.
    • 2000, Pete Fowler, Keeps, page 62:
      In his room, he could install his infrareds without being discovered.
    • 2007, Ed Morawski, Solving the Security Puzzle, page 79:
      Beams are the active counterparts of passive infrareds (PIRs). Since these are active infrareds, they require two parts: a transmitter and a receiver.
    • 2020, Jenny Dorsey, The Infrared Grill Master: Recipes and Techniques for Perfectly Seared, Deliciously Smokey BBQ Every Time:
      Additionally, infrareds tend to cook food faster so there's less time to render said fat.



infrared (not comparable)

  1. Having a wavelength in the infrared spectrum.
    Hyponyms: mid-infrared, near-infrared
  2. (figurative, physics) Relating to very low energies or very large distances or time spans.
    Antonym: ultraviolet
    • 1986, Luis Álvarez-Gaumé, “An Introduction to Anomalies”, in G. Velo, A. S. Wightman, editors, Fundamental Problems of Gauge Field Theory, →ISBN, page 97:
      Unless otherwise stated, we will be working in Euclidean space compactified to a sphere in order to avoid infrared problems.
    • 2000, Andreas Galka, Topics in Nonlinear Time Series Analysis: With Implications for EEG Analysis, →ISBN, page 176:
      Secondly, as stated already by Osborne & Provenzale, pure k-behaviour is impossible since there would have to be infinite power at zero frequency (this would correspond to an infrared catastrophe).
    • 2010, Taizo Muta, Foundations of Quantum Chromodynamics: An Introduction to Perturbative Methods in Gauge Theories, 3rd edition, →ISBN, page 331:
      Although infrared divergences are of long-distance nature, they often play an essential role in the verification of the validity of the perturbative treatment of short-distance phenomena.

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