Quiz: Remember the definition of mal de mer?


[in-fruh-red] /ˌɪn frəˈrɛd/
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.
noting or pertaining to the infrared or its component rays:
infrared radiation.
Also, infra-red.
Compare ultraviolet.
1825-35; infra- + red1 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
Cite This Source
Examples from the web for infrared
  • It is replaced by rays of infrared light spreading throughout the room.
  • Surface measurements find more downward infrared radiation warming the planet's surface.
  • Because rattlesnakes can sense infrared radiation, a hot tail makes the ground squirrel look even bigger.
  • They've got an infrared heat lamp to keep them toasty as they grow, and they've gotten lots of visitors today.
  • Objects with strong infrared readings are earmarked: these may be distant quasars.
  • It carries radar and two sets of sensors, electro-optical and infrared.
  • Images produced with color infrared film have a unique look.
  • The infrared spectral region is ideal for observing cool sources and objects enshrouded in dust.
  • Using an infrared generator also partially solves the problem of ambient light.
  • infrared light used for terrestrial observation decays rapidly in seawater, limiting its utility in ocean exploration.
British Dictionary definitions for infrared


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
of, relating to, using, or consisting of radiation lying within the infrared: infrared 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
Cite This Source
infrared in Medicine

infrared in·fra·red (ĭn'frə-rěd')

  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.

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.
Cite This Source
infrared in Science
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.

Our Living Language  : 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 © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
infrared in Technology
(IR) Electromagnetic waves in the frequency range just below visible light corresponding to radiated heat. IR waves can be generated by a kind of LED and are often used for remote controls for televisions etc. and in some docking stations.
The Free On-line Dictionary of Computing, © Denis Howe 2010
Cite This Source

Word of the Day

Difficulty index for infrared

Most English speakers likely know this word

Word Value for infrared

Scrabble Words With Friends

Nearby words for infrared