English
lightshift
From light + shift.
Proto-Indo-European *lewk- ‘to shine’
…
Proto-Germanic *leuhtą
Proto-West Germanic *leuht ‘light’
Old English lēoht
Middle English light ‘light, illumination’
English light
Proto-Indo-European *skey- ‘to cut’
…
Proto-Germanic *skiftijaną ‘to divide’
Proto-West Germanic *skiftijan
Old English sċiftan ‘to divide’
Middle English schiften ‘to split’
English shift
Today it means
noun The change in the energy (and thus frequency) of light upon interaction with matter.
Language periods are conventional ranges, not dates for this word.
Etymograph / lightshift