Natural Phenomenon or Process
infrared rays
in·fra·red rays
Definitions related to infrared rays:
  • That portion of the electromagnetic spectrum usually sensed as heat. Infrared wavelengths are longer than those of visible light, extending into the microwave frequencies. They are used therapeutically as heat, and also to warm food in restaurants.
    NLM Medical Subject Headings
    U.S. National Library of Medicine, 2025
  • (infrared radiation) Electromagnetic radiation at wavelengths longer than the red end of visible light and shorter than microwaves (roughly between 1 and 100 microns); infrared is usually divided into 3 spectral regions, near, mid and far-infrared.
    CRISP Thesaurus
    National Institutes of Health, 2006
  • (infrared radiation) Electromagnetic radiation with wavelengths between 750 nanometers and 1 millimeter, between those of visible light and microwaves. This portion of the electromagnetic spectrum can usually be sensed as heat.
    NCI
    U.S. National Cancer Institute, 2021
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This content should not be used in place of medically-reviewed decision support reference material or professional medical advice. Some terms may have alternate or updated definitions not reflected in this set. The definitions on this page should not be considered complete or up to date.