infrared

adjective

in·​fra·​red ˌin-frə-ˈred How to pronounce infrared (audio)
-(ˌ)frä-, 
-fə-
1
: situated outside the visible spectrum at its red end
—used of radiation having a wavelength between about 700 nanometers and 1 millimeter
2
: relating to, producing, or employing infrared radiation
infrared therapy
3
: sensitive to infrared radiation
infrared sensors that detect body heat
infrared noun

Examples of infrared in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Products measure infrared rejection, UV protection and total solar energy reduction differently, making those numbers tough to compare across brands. — Ryan Brennan, Fort Worth Star-Telegram, 1 Sep. 2026 Outfitted with two primary instruments, the observatory provides a large field of view with crisp infrared vision to explore vast swaths of the sky. — Eric Lagatta, USA Today, 31 Aug. 2026 Besides a wide-field infrared camera that matches Hubble’s sensitivity but is 1,000 times faster, Roman holds an instrument to block out starlight. — Marcia Dunn, Fortune, 30 Aug. 2026 In this location, the telescope will rarely be blocked by Earth and infrared heat from the Earth, sun and moon is minimized. — Matthew Glasser, ABC News, 29 Aug. 2026 See All Example Sentences for infrared

Word History

First Known Use

1881, in the meaning defined at sense 1

Time Traveler
The first known use of infrared was in 1881

Phrases Containing infrared

Rhymes for infrared

See All Rhymes for infrared

Browse Nearby Words

infra praesidia
infrared
infrared lamp
See all Nearby Words

Cite this Entry

“Infrared.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/infrared. Accessed 4 Sep. 2026.

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Kids Definition

infrared

adjective
in·​fra·​red ˌin-frə-ˈred How to pronounce infrared (audio)
-(ˌ)frä-
: being, relating to, producing, or using rays like light but lying outside the visible spectrum at its red end
infrared radiation
infrared noun

Medical Definition

infrared

1 of 2 adjective
in·​fra·​red ˌin-frə-ˈred How to pronounce infrared (audio)
1
: lying outside the visible spectrum at its red end
—used of radiation having a wavelength between about 700 nanometers and 1 millimeter
2
: relating to, producing, or employing infrared radiation
infrared therapy

infrared

2 of 2 noun
: infrared radiation
Last Updated: - Updated example sentences
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