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

Other companies, such as BlackSky and Maxar, are providing their own electro-optical/infrared (EO/IR) imagery—that is, images in the visible and infrared light spectrums—commercially. —Literary Hub, 28 Oct. 2025

The glasses capture images and send them as near-infrared light to the implant. —Kurt Knutsson, FOXNews.com, 28 Oct. 2025

This mask uses four light wavelengths—amber (605nm), red (630nm), deep red (660nm), and infrared (880nm)—to target wrinkles around the eye area in just three minutes. —Deanna Pai, Vogue, 27 Oct. 2025

The improvements in that technology transferred to the health industry, enabling smaller, less expensive infrared devices for a number of medical applications such as handheld ear thermometers used at home and sophisticated instruments used to detect cancers. —Michele Raphael, USA Today, 24 Oct. 2025

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