Where does “squirrel-proof” come from?

squirrel-proof (English) comes from English proof, from Middle English proof, from Old French prove, from Latin proba, from Latin probāre, from Latin probō, from Latin Probus, from Proto-Indo-European pro-bhwo- — passed , crossed.

Ancestry of “squirrel-proof”, step by step

squirrel-proof traces back through two separate lines of ancestry.

via English proof

StepLanguageWordMeaning
1EnglishproofAn effort, process, or operation designed to...
2Middle Englishproof
3Old Frenchprove
4Latinprobatest, trial; proof, evidence
5Latinprobāre
6Latinprobōto approve, permit, commend
7LatinProbusgood, serviceable, excellent, superior, able
8Proto-Indo-Europeanpro-bhwo-being in front, prominent
9Proto-Indo-Europeanpro-toward, forward
10Proto-Indo-Europeanpor-to give birth; forward, through; going, passage
11Proto-Indo-Europeanper-before, in front; first; to go through
12Proto-Indo-Europeanpr̥tóspassed , crossed

via English squirrel

StepLanguageWordMeaning
1EnglishsquirrelAny of the rodents of the family Sciuridae...
2Middle EnglishsquirelA squirrel; A squirrel fur or hide
3Old Frenchescurelsquirrel
4Vulgar Latinscuriolus
5Latinscūrius
6Latinsciūrussquirrel
7Ancient Greekσκίουροςsquirrel
8Ancient Greekσκιάshadow; shade
9Proto-Indo-European(s)ḱeh₃ih₂shadow, shade
10Proto-Indo-European(s)ḱeh₃-darkness, shadow
Every word from Proto-Indo-European pr̥tósEvery word from Proto-Indo-European per-Every word from Proto-Indo-European por-