Where does “downsies” come from?

downsies (English) comes from English Down, from Middle English doun, from Old English dūn, from Proto-Germanic *dūnā, from Proto-Celtic dūnom, from Proto-Indo-European dʰewh₂- — smoke; mist, haze.

Ancestry of “downsies”, step by step

downsies traces back through two separate lines of ancestry.

via English Down

StepLanguageWordMeaning
1EnglishDownusually known as County Down
2Middle Englishdoundown
3Old Englishdūnhill, down; hill, dune; hill, mountain
4Proto-Germanic*dūnā
5Proto-Celticdūnomstronghold, rampart
6Proto-Indo-Europeandʰewh₂-smoke; mist, haze

via English sies

StepLanguageWordMeaning
1EnglishsiesExpressing disgust, disappointment, or annoyance;...
Every word from Proto-Indo-European dʰewh₂-Every word from Proto-Celtic dūnomEvery word from Proto-Germanic *dūnā