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infrared

or in·fra-red

[in-fruh-red]
See more synonyms on Thesaurus.com
noun
  1. the part of the invisible spectrum that is contiguous to the red end of the visible spectrum and that comprises electromagnetic radiation of wavelengths from 800 nm to 1 mm.
adjective
  1. noting or pertaining to the infrared or its component rays: infrared radiation.
Compare ultraviolet.

Origin of infrared

First recorded in 1825–35; infra- + red1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for infrared

Contemporary Examples

Historical Examples

  • Malone flicked on the infrared flashlight he held in his hand.

    Out Like a Light

    Gordon Randall Garrett

  • The infrared detector gave him no range information, of course.

    Pushbutton War

    Joseph P. Martino

  • Their vision range is from just within the visible red on into the infrared.

  • He pressed the infrared switch and heard the dynamo whine softly.

    Smugglers' Reef

    John Blaine

  • His eye found the telescope and he pressed the infrared switch.

    Smugglers' Reef

    John Blaine


British Dictionary definitions for infrared

infrared

noun
  1. the part of the electromagnetic spectrum with a longer wavelength than light but a shorter wavelength than radio waves; radiation with wavelength between 0.8 micrometres and 1 millimetre
adjective
  1. of, relating to, using, or consisting of radiation lying within the infraredinfrared radiation
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

infrared in Medicine

infrared

([object Object])
adj.
  1. 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.
  2. Generating, using, or sensitive to infrared radiation.
n.
  1. Infrared light or the infrared part of the spectrum.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

infrared in Science

infrared

[ĭn′frə-rĕd]
  1. Relating to the invisible part of the electromagnetic spectrum with wavelengths longer than those of visible red light but shorter than those of microwaves. See more at electromagnetic spectrum.
A Closer Look: In 1800 the astronomer Sir William Herschel discovered infrared light while exploring the relationship between heat and light. Herschel used a prism to split a beam of sunlight into a spectrum and then placed a thermometer in each of the bands of light. When he placed the thermometer just outside the red band, where there was no visible color, the temperature rose, as if light were shining on the thermometer. Further experiment showed that this invisible radiation behaved like visible light in many ways; for example, it could be reflected by a mirror. Infrared radiation is simply electromagnetic radiation with a lower frequency than visible light, having longer wavelengths of 0.7 micrometer to 1 millimeter. Ultraviolet radiation, like infrared radiation, lies just outside the visible part of the spectrum, but with higher frequencies; some animals, such as bees, are capable of seeing such radiation. Both infrared and ultraviolet radiation are often referred to as forms of light, though they cannot be seen by human beings. Heat energy is often transferred in the form of infrared radiation, which is given off from an object as a result of molecular collisions within it. Molecules typically have a characteristic infrared absorption spectrum, and infrared spectroscopy is a common technique for identifying the molecular structure of substances. Astronomers similarly analyze the infrared radiation emitted by celestial bodies to determine their temperature and composition.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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