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

Backed Beauty Devotee This LED mask uses red, near-infrared and deep near-infrared LED light to target skin tone, elasticity and aging—bringing spa-level treatment into the home. —Melissa Fleur Afshar, MSNBC Newsweek, 10 Dec. 2025

However, the sad truth is that those who have turned to traditional digital cameras and infrared sensors often face frustrations when visibility drops, especially when the weather is rainy, foggy, or even when darkness falls. —Malana Vantyler, USA Today, 10 Dec. 2025

According to Aetherflux's design, many small satellites will transmit energy through infrared lasers to ground stations, where the power and data can be subsequently distributed. —Josh Dinner, Space.com, 9 Dec. 2025

The brand pairs red and near-infrared light for aging concerns and blue light for breakouts. —Christa Joanna Lee, Allure, 8 Dec. 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