An Etymological Dictionary of the German Language/Annotated/Schloß

by Friedrich Kluge

Schloß, neuter, ‘lock, clasp; castle, palace,’ from Middle High German slō̆ȥ, neuter, ‘bolt, band, lock, fetter, castle, citadel,’ Old High German slŏȥ, neuter, ‘lock, bolt’; corresponding to Northern English slot, sloat, ‘bolt, crossbar’; allied to schließen.