English
radiation
Radiation comes from Latin radiatio ‘glittering, shining, radiation’, from radiō ‘to gleam, shine, beam’, and perhaps ultimately from Proto-Indo-European *neredʰ- ‘extend forth, rise, outward’.
- Proto-Indo-Europeanc. 4500–2500 BCE*neredʰ-1‘extend forth, rise, outward’uncertain
- Latinc. 75 BCE–200 CEradius2‘the radius of a circle’
- Latinc. 75 BCE–200 CEradiō2‘to gleam, shine, beam’
- Latinc. 75 BCE–200 CEradiatio3as radiatio‘glittering, shining, radiation’
- Englishearliest quotation 1986radiation3
attested reconstructed ? uncertain or disputed deepest recorded ancestor
- 1 Wiktionary, Latin radius
- 2 Wiktionary, Latin radiatio
- 3 Wiktionary, English radiation
- Earliest quotation in Wiktionary’s entry: 1986, "Weird Al" Yankovic, Christmas at Ground Zero: “It's Christmas at ground zero / And if the…”.
Lineage
- Proto-Indo-Europeanc. 4500–2500 BCE*neredʰ-Wiktionary, Latin radius‘extend forth, rise, outward’uncertain
- Latinc. 75 BCE–200 CEradiusWiktionary, Latin radiatio‘the radius of a circle’
- Latinc. 75 BCE–200 CEradiōWiktionary, Latin radiatio‘to gleam, shine, beam’
- Latinc. 75 BCE–200 CEradiatioWiktionary, English radiationas radiatio‘glittering, shining, radiation’
- Englishearliest quotation 1986radiationWiktionary, English radiation. Earliest quotation in Wiktionary’s entry: 1986, "Weird Al" Yankovic, Christmas at Ground Zero: “It's Christmas at ground zero / And if the…”
Linked words
through Latin radius ‘the radius of a circle’
through Latin radiatio ‘glittering, shining, radiation’
Today it means
noun The shooting forth of anything from a point or surface, like diverging rays of light.
Sources
Sources: Wiktionary, “radiation”; the older steps come from the Wiktionary entries for Latin radius, Latin radiatio. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.
Etymograph / Proto-Indo-European *neredʰ- / radiation