Infrared
/ˌɪnfrəˈrɛd/noun
Electromagnetic radiation with wavelengths longer than visible red light, felt as heat.
Did you know?The term was coined after William Herschel discovered in 1800 that there was invisible radiation beyond the red end of the spectrum, proving light had hidden territories no eye could detect.
Etymological Timeline
Latin
Latin
infra
“below; beneath”
Late Latin
Latin
ruber
“red”
1800
English
infra-red
“a type of invisible radiation beyond the red end of the spectrum”
19th Century
English
infrared
“the part of the spectrum below red light, invisible to the eye”
Modern English
English
infrared
“electromagnetic radiation with wavelengths longer than visible red light”
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