An Etymological Dictionary of the German Language/Annotated/löschen
löschen (1.), verb, ‘to extinguish, go out’; in the Modern High German verb two Middle High German verbs are comprised, Middle High German lëschen (most frequently erlëschen), strong verb, ‘to cease to burn, go out,’ and the corresponding factitive lęschen, ‘to extinguish’; compare Old High German lëskan, irlëskan, intransitive, and lęsken, transitive; this verbal stem is unknown to the other Teutonic languages. The sk of Old High German lëskan is really a suffix of the present stem (see dreschen and waschen), as may be inferred from the connection with the Teutonic root leg (see liegen); erlöschen is literally ‘to lie down.’
löschen (2.), verb, ‘to discharge a ship,’ borrowed from the equivalent Low German, Dutch lossen; compare Danish losse, Swedish lossa; the origin and early history of the cognates are unknown (compare Boot, Bord, and Rahe).