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

Prefab kits and plug-in infrared units have brought entry prices lower than most people expect, though hidden costs like electrical upgrades and ventilation still catch buyers off guard. — Allison Palmer updated June 25, Charlotte Observer, 25 June 2026

Next Health’s most popular IV membership, at $299 a month, bundles two IV drips, two vitamin shots and monthly access to cryotherapy, infrared LED, hyperbaric oxygen and body composition scans, which is a useful benchmark for how the membership math actually works at a mid-tier clinic. — Allison Palmer updated June 24, Sacbee.com, 24 June 2026

The Light Straight + Multi-styler uses patented near-infrared light to reshape hair’s internal hydrogen bonds at under 320 degrees Fahrenheit, staying below the 400-degree threshold at which keratin begins to denature. — Allison Palmer updated June 24, Fort Worth Star-Telegram, 24 June 2026

For body recovery, joint pain or full-body wellness, panels delivering 660nm red plus 850nm near-infrared cover the most use cases. — Allison Palmer updated June 24, Miami Herald, 24 June 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