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 sanctuary offers five hydrotherapy pools, eight treatment rooms, a fitness center and movement studio, a steam room, and dry and infrared saunas. — Fairchild Studio, Footwear News, 19 Aug. 2026

To capture this incredible composite view of the galaxy, astronomers combined near and mid-infrared wavelength observations made by JWST and ultraviolet, visible and near-infrared observations made by Hubble. — Chelsea Gohd, Space.com, 18 Aug. 2026

Its equipment can boost radar and infrared signatures, provide electronic support, jam signals, use countermeasures, and carry out attack missions. — Sujita Sinha, Interesting Engineering, 17 Aug. 2026

By analyzing the star's infrared light with the Webb telescope, the research team identified signs of oxygen-rich dust and, for the first time, detected water in the star's surrounding envelope. — CBS News, 12 Aug. 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