I. |infrə|red, -ˌfrä|-, -ˌfrȧ|- sometimes |infə|r- by r-dissimilation adjective
Etymology: infra- + red
1. : lying outside the visible spectrum at its red end — used of thermal radiation of wavelengths longer than those of visible light
2. : relating to, producing, or employing infrared radiation
infrared therapy
infrared photography
3. : sensitive to infrared radiation and capable of photographing in darkness or through haze
infrared film
II. noun
: infrared radiation