Where does “vache folle” come from?

vache folle (French) comes from French vache, from Old French vache, from Latin vacca, from Proto-Indo-European wokeh₂-.

vache folle (French): mad cow

Definitions

  1. mad cow

Ancestry of “vache folle”, step by step

vache folle traces back through two separate lines of ancestry.

via French vache

StepLanguageWordMeaning
1Frenchvachecow; harsh; nasty
2Old Frenchvachecow
3Latinvaccacow
4Proto-Indo-Europeanwokeh₂-

via French folle

StepLanguageWordMeaning
1Frenchfollefeminine singular of fou; madwoman; queen
Every word from Proto-Indo-European wokeh₂-Every word from Latin vaccaEvery word from Old French vache
vache folle — Etymology, Origin & Word History | Etymology Explorer