An Etymological Dictionary of the German Language/Annotated/Loch

by Friedrich Kluge

Loch, neuter, ‘hole, dungeon, haunt,’ from Middle High German loch, neuter, Old High German loh, genitive lohhes, neuter, ‘enclosed place, prison, lurking-place, cave, hole, opening.’ Compare Anglo-Saxon loc, neuter, ‘enclosed place, lock’; loca, masculine, ‘enclosed place, prison’; from the former English lock is derived. The various meanings all originate in ‘enclosed place’; compare Gothic usluka-, ‘opening.’ The substantive is formed by gradation from an old Teutonic verb (obsolete in Modern High German), Middle High German lûchen, Old High German lûhhan, Gothic lûkan, Anglo-Saxon lûcan, ‘to lock,’ which may be compared (since the Pre-Teutonic root is lū̆g) with Lithuanian lúżtu (lúżti), ‘to be broken,’ as well as with Sanscrit ruj, ‘to break.’