infrared

IPA/ˌɪnfrəˈred/
KK[ˌɪnfrɚˈɛd]IPA/ˌɪnfrəˈred/

infrared — adjective

  • infraredpositive
  • more infraredcomparative
  • most infraredsuperlative

1. describing a type of invisible light whose wavelength is longer than that of red

1.adjectiveB2
Definition

describing a type of invisible light whose wavelength is longer than that of red light. Human eyes cannot see it, but the skin can feel it as warmth.

Example

An infrared light above the front door helped the camera record visitors in complete darkness.

infrared + noun for technology applications

Meteorologists use infrared satellite images to track the temperature of clouds during a storm.

infrared + noun in scientific context

Common collocations
  • infrared light
  • infrared radiation
  • infrared camera
  • infrared sensor
  • infrared heater
  • infrared thermometer
  • infrared image
Synonyms
  • thermal

    broader term covering any heat-related phenomenon; infrared specifically refers to a precise wavelength range

Antonyms
  • ultraviolet

    radiation at the opposite end of the visible spectrum, with shorter wavelengths than violet light

Grammar Patterns

infrared + noun

Usage Note

Infrared is almost always used before a noun (attributive position). Common noun partners include 'light', 'radiation', 'camera', 'sensor', 'heater', 'thermometer', and 'image'.

Common Mistakes

The sun gives off infrareds that warm the Earth.
The sun gives off infrared radiation that warms the Earth.
Infrared is an adjective or non-count noun; it does not take a plural -s ending.

Synonym discussion

Sense: adjective/1

Infrared, thermal, and ultraviolet all describe types of radiation, but they differ in wavelength and how humans perceive them. Infrared refers specifically to radiation with a wavelength just beyond red light, which people feel as heat but cannot see. Thermal is a broader term that describes anything related to heat — a thermal blanket keeps heat in, while an infrared heater produces a specific kind of heat radiation. Ultraviolet sits at the opposite end of the visible spectrum, with shorter wavelengths than violet light; it causes sunburn but is not felt as warmth. In weather reports, infrared satellite images show cloud temperature, whereas ultraviolet index measures sunburn risk.

infrared ↗thermal ↗ultraviolet ↗

Common collocations

Nouns

Phrases

  • infrared light
  • infrared radiation
  • infrared camera
  • infrared sensor
  • infrared heater
  • infrared thermometer
  • infrared image
  • far infrared
  • near infrared

Etymology

LatinEnglish

Formed from the Latin prefix infra-, meaning 'below' or 'beyond', and the English word red. The name refers to the fact that the wavelength of this radiation falls just beyond the red end of the visible light spectrum.