infrared

adjective

in·​fra·​red ˌin-frə-ˈred 

-(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

The Netherlands and Belgium are testing for several crops a tiny drone that, using infrared light, can detect moths and chop them in half in mid-air. —Shaun McKinnon, The Arizona Republic, 14 Oct. 2024

Recently, a separate team of astronomers peered into the heart of the Great Red Spot using the James Webb Space Telescope to capture new details in infrared light. —Ashley Strickland, CNN, 11 Oct. 2024

Peer through the device’s viewfinder while scanning the room with its infrared light. —Stack Commerce, Popular Science, 10 Oct. 2024

Several people looked forward to being able to combine JWST measurements with ones from the Nancy Grace Roman Space Telescope, which like JWST will observe infrared light from the early universe to tackle cosmological questions. —Rebecca Boyle, Quanta Magazine, 9 Oct. 2024

Word History

First Known Use

1881, in the meaning defined at sense 1

Phrases Containing infrared

• far-infrared
• near-infrared

Kids Definition

infrared

adjective

in·​fra·​red ˌin-frə-ˈred 

-(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 

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