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

This specialized approach involves rotating between 15 minutes in an infrared sauna and 30-minute periods wrapped in blankets to retain heat. —Mark Gurarie, Verywell Health, 17 Feb. 2026

The primary bath is massive with an infrared sauna, and the closet is decked out with cornflower-blue accents. —Tori Latham, Robb Report, 16 Feb. 2026

Investigators believe the face mask the suspect wore is black but appears lighter on the video footage due to Nest camera's infrared technology. —Kiki Intarasuwan, CBS News, 16 Feb. 2026

For recovery and contrast therapy, Verde features infrared saunas, a traditional Finnish sauna that heats up to 190°F, hot tubs and cold plunges. —Karen Billing, San Diego Union-Tribune, 16 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