Etymology
From Middle English *galowen, *galewen, *galwen (attested in begalewen (“to frighten”)), from Old English *gǣlwan, *gēlwan (attested in āgǣlwed, āgēlwed (“stupified, astonished, disconcerted”)), of unknown origin. Alternative forms gally, galley perhaps influenced by Middle English galyen, galien, variants of galen (“to cry out, shout, make a harsh cry”), from Old English galan (“to sing, call”). Compare also Old Norse gala (“to sing, shout, crow”), Old Norse gjalla (“to yell, shout”).