Infrared Ray
/ˌɪn.frəˈrɛd reɪ/noun
A beam or form of electromagnetic radiation with wavelengths longer than visible red light.
Did you know?William Herschel discovered infrared radiation in 1800 by measuring heat beyond the red end of a sunlit spectrum, making it the first invisible electromagnetic radiation to be identified.
Etymological Timeline
Proto-Indo-European
PIE
*en- / *ndher-
“Roots associated with being in, within, or below; these contributed to Latin positional terms.”
Classical Latin
Latin
īnfĕrā
“Below, underneath, or beneath.”
Classical Latin
Latin
rādius
“A staff, spoke of a wheel, ray, or beam of light.”
17th Century
Latin/English
infra-
“A learned prefix meaning below or beneath, used in scientific terminology.”
1800
English
infra-red
“A radiation region beyond the red end of the visible spectrum, identified through Herschel's experiments.”
Modern English
English
infrared ray
“A beam or wavelength of invisible electromagnetic radiation experienced primarily as heat.”