Where does “stopgap” come from?

Stopgap comes from English stop and English gap, where stop derives from Old English stoppian, from Proto-Germanic stuppōną, ultimately from Proto-Indo-European (s)tew- meaning to push or thrust.

stopgap (English): Filling a gap or pause; Temporary; short-term;...

Definitions

  1. Filling a gap or pause; Temporary; short-term;...

Ancestry of “stopgap”, step by step

stopgap traces back through two separate lines of ancestry.

via English stop

StepLanguageWordMeaning
1EnglishstopTo cease moving; To not continue; To cause to...
2EnglishtopThe highest or uppermost part of something; A...
3Middle EnglishtopThe summit or top of something, especially a...
4Old Englishtopptop, summit (of something)
5Proto-West Germanic*topptop, summit, crest
6Proto-Germanictuppaztuft, plait; top, summit
7Proto-Indo-Europeandumb-tail, rod, staff, pole, penis; tail, rod, staff,...

via English gap

StepLanguageWordMeaning
1EnglishgapAn opening in anything made by breaking or...
2EnglishgapeTo open the mouth wide, especially involuntarily,...
3Middle Englishgapen
4Old Norsegapato gape, open the mouth wide
5Proto-Germanicgapōnąto gaze, observe
6Proto-Indo-Europeanǵʰeh₁y-to yawn, gape; to gape, be wide open; to gape,...
7Proto-Indo-Europeanǵʰih₁-
Every word from Proto-Indo-European dumb-