köken: First attested in the Seokbo sangjeol (釋譜詳節 / 석보상절), 1447, as Middle Korean ᄌᆞ올다〮 (Yale: còwòl-tá). The pre-Middle Korean form is reconstructed as *ᄌᆞᄇᆞᆯ *copol- on the strength of modern dialectal forms with /-p-/ in this word. Perhaps related to 자다 (jada, “to sleep”).