Where does “spillover” come from?

Spillover comes from English spill, from Middle English spillen, from Old English spillan, from Proto-Germanic spillijaną, ultimately from Proto-Indo-European (s)pel- and upo.

spillover (English): That which overflows; the excess or side effect;...

Definitions

  1. That which overflows; the excess or side effect;...

Ancestry of “spillover”, step by step

spillover traces back through two separate lines of ancestry.

via English over

StepLanguageWordMeaning
1EnglishoverDiscontinued; ended or concluded; Thoroughly;...
2Middle Englishoverriverbank, seashore, brink
3Old Englishōferriverbank, seashore, brink, edge, margin, border
4Proto-West Germanicobarover, above
5Proto-Germanicuberover; over, above
6Proto-Indo-Europeanupérabove; over
7Proto-Indo-Europeanupóunder, below
8Proto-Indo-Europeanh₃ewp-

via English spill

StepLanguageWordMeaning
1EnglishspillTo drop something so that it spreads out or makes...
2Middle EnglishspillenTo slaughter, eliminate; to cause the death of;...
3Old Englishspillanto destroy; spill
4Proto-Germanicspillijanąto split
5Proto-Indo-Europeanspel-to break; to break off, split; to cleave, break
Every word from Proto-Indo-European h₃ewp-Every word from Proto-Indo-European upóEvery word from Proto-Indo-European upér
spillover — Etymology, Origin & Word History | Etymology Explorer