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 hotel’s spa, Astraea, is home to two massage rooms, a set of meditation loungers, and two private infrared sauna suites available to book. —Jacqueline Dole, Travel + Leisure, 5 June 2024

Above you, a field of 60 rectangular light boxes cycles through the visible spectrum from the edge of ultraviolet to nearly infrared. —Siddhartha Mitter, New York Times, 10 May 2024

Messier 78’s dusty clouds would normally shield these subjects from view, but the telescope’s infrared vision can peer through the wispy matter. —Christian Thorsberg, Smithsonian Magazine, 24 May 2024

The exoplanet’s atmosphere (which may or may not exist) will be a primary focus of future studies, particularly with the James Webb Telescope, which is well-suited for analyzing the chemical composition of planetary atmospheres through its advanced infrared capabilities. —George Dvorsky / Gizmodo, Quartz, 23 May 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