Where does “adowne” come from?

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

Ancestry of “adowne”, step by step

StepLanguageWordMeaning
1Old Englishadūndown, downward
2Old Englishofdūneoff the hill; down
3Old Englishdūnhill, down; hill, dune; hill, mountain
4Proto-Germanic*dūnā—
5Proto-Celticdūnomstronghold, rampart
6Proto-Indo-Europeandʰewh₂-smoke; mist, haze
Every word from Proto-Indo-European dʰewh₂- →Every word from Proto-Celtic dūnom →Every word from Proto-Germanic *dūnā →