出典:Wiktionary
From Middle English on heigh, on an heigh (“in または into heaven; up to heaven”) [and other forms],[1] from 古期英語 on hēagum (“on high”); hēagum is an inflected form of hēah (“high; tall”), ultimately from Proto-Indo-European *kewk- (“height; to elevate”). The English word is equivalent to on + high. Compare Dutch omhoog (“upwards, on high”), West Frisian omheech (“upwards”).