Where does “halowen” come from?

halowen (Middle English) comes from Middle English halow, from Old English ēalā — O!, alas!, oh!, lo!.

Ancestry of “halowen”, step by step

StepLanguageWordMeaning
1Middle Englishhalow—
2Old EnglishēalāO!, alas!, oh!, lo!
Every word from Old English ēalā →Every word from Middle English halow →