Where does “lightlike” come from?

lightlike (English) comes from English like, from Dutch luik, from Middle Dutch luke, from Dutch luiken, from Middle Dutch luken, from Old Dutch lūcan, from Proto-West Germanic lūkan, from Proto-Germanic lūkaną — to break, tear; to break, shatter.

lightlike (English): Having a space component whose magnitude is equal...

Definitions

  1. Having a space component whose magnitude is equal...

Ancestry of “lightlike”, step by step

lightlike traces back through two separate lines of ancestry.

via English like

StepLanguageWordMeaning
1EnglishlikeTo enjoy, be pleased by; favor; be in favor of;...
2Dutchluikhatch; shutter; panel, as in a triptych
3Middle Dutchluke
4Dutchluikento close, to shut
5Middle Dutchlukento close, to shut; to close, to become closed
6Old Dutchlūcanto close, shut
7Proto-West Germaniclūkanto close, to shut
8Proto-Germaniclūkanąto close, to shut; Alternative form of *leukaną
9Proto-Indo-Europeanlewǵ-to break, tear; to break, shatter

via English Light

StepLanguageWordMeaning
1EnglishLightA place name
2Middle EnglishlightThe radiation which allows for vision by...
3Old Englishlēohtluminous, bright, light, clear, resplendent,...
4Proto-West Germanicleuhtlight, bright; light
5Proto-Germanicleuhtąlight
6Proto-Indo-Europeanlewktom
7Proto-Indo-Europeanlewk-bright; to shine; to see
Every word from Proto-Indo-European lewǵ-Every word from Proto-Germanic lūkanąEvery word from Proto-West Germanic lūkan