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

At the opposite end, the basement holds a gym and an infrared sauna. —Wendy Bowman, Robb Report, 5 Mar. 2026

Camouflage, decoys, and deception Visual and infrared camouflage, decoys, and fake launchers together form a strategy Iran uses to confuse surveillance systems such as satellites and reconnaissance aircraft, in a bid to defend its ballistic missile systems. —Atharva Gosavi, Interesting Engineering, 4 Mar. 2026

NIRCam captures shorter-wavelength infrared light that highlights the stars and star clusters embedded deep within the spiral arms. —Daisy Dobrijevic, Space.com, 4 Mar. 2026

Massages aren’t done randomly — thermal body mapping uses infrared to show asymmetries and muscle tightness so that specific areas of tension can be addressed. —Beth Landman, HollywoodReporter, 28 Feb. 2026

Word History

First Known Use

1881, in the meaning defined at sense 1

Phrases Containing infrared

• far-infrared
• near-infrared

Rhymes for infrared

• abovesaid
• aforesaid
• arrowhead
• casinghead
• copperhead
• figurehead
• fountainhead
• gingerbread
• hammerhead
• leatherhead
• letterhead
• loggerhead

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