light
The natural agent that stimulates sight and makes things visible; electromagnetic radiation.
Etymology
From Old English lēoht (light, brightness), from Proto-Germanic *leuhtą, from PIE *lewk- (light, brightness). This is one of the best-attested PIE roots. Latin lūx (light), lūcēre (to shine), and lūna (moon — 'the shining one') all derive from it, as do Greek leukos (white, bright) and Sanskrit rocate (it shines). The English words luminous, lunar, and lucid enter through the Latin branch.
The Journey: *lewk- → light
*lewk-
*leuhtą
lēoht
light
Cognates Across Languages
These words in other languages descend from the same PIE root *lewk-. They are not borrowings but independent inheritances from a common ancestor.
| Language | Word |
|---|---|
| Greek | leukos (λευκός) — white, bright |
| Latin | lūx — light |
| Sanskrit | rocate — it shines |
| Old Irish | lóche — lightning |
| Lithuanian | laukas — pale |
Did You Know?
Light, lunar, luminous, lucid, and Lucifer ('light-bearer') all descend from PIE *lewk-. Lucifer was originally just a Latin name for the morning star — the 'bringer of light' before dawn.
This word descends from the Proto-Indo-European root *lewk-. See the full root page for descendant trees, sound law references, and scholarly discussion.