English
looplight
From loop + light.
Proto-Indo-European *klewb- ‘to spring’
Proto-Germanic *hlaupaną ‘to leap, run’
Old Norse hlaupa ‘to leap’
Old Norse hlaup ‘a run’
Middle English loupe ‘noose, loop’
English loop
Proto-Indo-European *lewk- ‘to shine’
…
Proto-Germanic *leuhtą
Proto-West Germanic *leuht ‘light’
Old English lēoht
Middle English light ‘light, illumination’
English light
Today it means
noun A small narrow opening or window in a tower or fortified wall
Language periods are conventional ranges, not dates for this word.
Etymograph / looplight