Definition of infrared in English:



  • 1(of electromagnetic radiation) having a wavelength just greater than that of the red end of the visible light spectrum but less than that of microwaves. Infrared radiation has a wavelength from about 800 nm to 1 mm, and is emitted particularly by heated objects.

    • ‘The molecules emit infrared light because they have absorbed ultraviolet radiation from the star or have been heated by the wind from the star.’
    • ‘Sunlight contains a range of electromagnetic radiation, mostly infrared and visible, but it is the UV radiation that is important from a biological point of view.’
    • ‘This dominates their infrared spectra, where wavelengths beyond 0.75 m are efficiently reflected away.’
    • ‘At the heart of the sensor is a liquid-nitrogen-cooled laser diode, which generates infrared light at the same wavelength as a molecular transition in ethane.’
    • ‘The materials and the thickness of the layer determine how much infrared radiation and visible light pass through the window.’
    • ‘It measures the infrared radiation they emit in 167 different wavelengths, providing information about the targets' composition.’
    • ‘Terahertz light is a little-studied realm of the electromagnetic spectrum between microwave and infrared light.’
    • ‘The sight does not emit visible or infrared light (except from the eyepiece) that can be detected by the enemy.’
    • ‘To cool a room, use fluorescent lights that don't emit infrared rays rather than using incandescent lights.’
    • ‘On the other hand, even tenuous cirrus clouds absorb significant amounts of thermal infrared radiation emitted by the ground and the lower atmosphere.’
    • ‘They zapped the clusters with infrared light and microwaves to make the molecules vibrate and spin.’
    • ‘This multi-channel infrared radiometer will measure a wide range of infrared light emitted by the atmosphere at several altitudes.’
    • ‘Stars like our Sun emit primarily in the visible region, and cooler objects like planets emit invisible infrared radiation.’
    • ‘Combining the data sets produced a single spectrum spanning visible and infrared wavelengths.’
    • ‘‘Each mineral has sort of a fingerprint in the visible to near infrared spectrum,’ explained Johnson.’
    • ‘The photocathode in the night scope that converts visible light into electrons is sensitive to both visible light and some infrared radiation.’
    • ‘It isn't hot enough to radiate UV rays but it does radiate in the visible and infrared parts of the electromagnetic spectrum.’
    • ‘The laser will use infrared light with a wavelength of 1.06 microns, which is thousands of times shorter than radio waves.’
    • ‘Viewing the visible and infrared light emitted by galaxies is crucial for determining their mass.’
    • ‘Tinted and mirrored films reduce the quantity of both visible light and infrared radiation entering the occupied space.’
    1. 1.1 (of equipment or techniques) using or concerned with infrared radiation.
      ‘infrared cameras’
      • ‘The grizzly bear cubs inhabiting the refuge atop Grouse Mountain are sleeping under the watchful eye of two infrared cameras.’
      • ‘Just this week, infrared cameras detected 15 people wending across the desert.’
      • ‘A dozen Army Technical Officers using high speed boats swooped on the Island and made a thorough search of the area using sophisticated infrared equipment.’
      • ‘Over a fortnight they used an infrared camera to check the switchgear equipment, which helps power the 1,132 ft long ship.’
      • ‘Ball lightning is a phenomenon that has been reported from naked eye sightings, not by people wearing or using infrared imaging equipment.’
      • ‘Our second piece of equipment was an infrared thermal camera, which shows differences in temperature across the surface of an animal as a false-color image.’
      • ‘The lights were filmed March 5 by pilots using infrared equipment.’
      • ‘In recent months, new surveillance equipment and infrared cameras have been installed.’
      • ‘It's so valuable that it's crowded out older, perfectly reasonable techniques like infrared spectroscopy.’
      • ‘But if that storm clears in time, the jets were going to get out with some infrared equipment and help with the search starting tomorrow.’
      • ‘He or she will use a variety of equipment such as blower doors, infrared cameras, and surface thermometers to find inefficiencies that cannot be detected by a visual inspection.’
      • ‘That is to say, with a set of infrared communication equipment, one can easily link a mobile phone to the Internet and freely download anything needed.’
      • ‘The unit's projector head, which incorporates a near - infrared camera, makes a real-time video image of the patient's blood and projects it back onto the patient's skin.’
      • ‘The aircraft was equipped with an infrared video camera and operated from the control tower at the Sentani Air Base near Jayapura.’
      • ‘It was decided previously infrared viewing equipment would be best.’
      • ‘He runs a company that makes infrared cameras and he hopes to do experiments while onboard the space station.’
      • ‘The commission has now set up an infrared camera in the Dumfries roost so that the bats' behaviour can be observed from below.’
      • ‘Investigators seemed baffled by the theft, as guards patrol the premises at night and there is tight security inside, including infrared systems and cameras.’
      • ‘Auditors from utilities may or may not use special equipment such as blower doors and infrared cameras, and they may or may not check the performance of your heating system.’
      • ‘A Western team filmed him with infrared cameras and, of course, were able to show that he was performing a conjuring trick.’


mass noun
  • The infrared region of the spectrum; infrared radiation.

    • ‘We now have eight sets of mirrors that cover the vibrational infrared from 2 to 11m.’
    • ‘Wavelengths of light in this region of the spectrum cause heating so blocking infrared reduces unwanted rays from the sun.’
    • ‘She claims there shouldn't be too much infrared around in the room (it's a large, fairly cool room, at night, cut into the side of a hill).’
    • ‘By mid-century, inroads were also being made into the near infrared.’
    • ‘But he said they are the most detailed ever made in UV and infrared, providing data that will be chewed on for some time.’
    • ‘Such methods include flight-call monitoring, radio telemetry, passive infrared, and radar.’
    • ‘Unlike infrared, you are not limited by line of sight.’
    • ‘But what is so special about water that makes its absorptions extend all the way from the far infrared to the near ultraviolet?’
    • ‘They made observations in four spectrum bands, from the visible through to the near infrared.’
    • ‘The detector range of the array spectrometer is 200 to 875 nm, from ultraviolet into the near infrared.’
    • ‘To warm the soil early in the season, mulch with black or infrared - transmitting plastic.’
    • ‘But the very same atmosphere is opaque in most frequencies of far infrared, ultraviolet, x-rays and gamma rays.’
    • ‘To obtain this measurement, the researchers use a combination of ultrasound and infrared.’
    • ‘There are of course lasers with wavelengths in the infrared, masers that emit coherent microwaves, and even x-ray lasers.’
    • ‘How does this jive with your saying it was only infrared?’
    • ‘The most modern missiles are not fooled by the flares, which is why the more expensive laser and infrared based systems are preferred.’
    • ‘He turned to the man outside who was watching the monitors of the woman that included infrared of her body temperature and sophisticated machinery that could detect the hint of a lie.’
    • ‘Better still might be a camera that sees in the thermal infrared.’
    • ‘However although his solution matches experimental observations closely for small values of the wavelength, it was shown to break down in the far infrared by Rubens and Kurlbaum.’
    • ‘The intensity of radiated light diminishes in the extreme ultraviolet and far infrared.’