An Etymological Dictionary of the German Language/Annotated/Zarge
Zarge, feminine, ‘border, edge, setting, groove,’ from the equivalent Middle High German zarge, Old High German zarga, feminine. Corresponding with as change of meaning to Anglo-Saxon and Old Icelandic targa, ‘shield’ (literally ‘shield border’), whence French targe, Italian targa, ‘shield’ (whence Middle High German and Modern High German tartsche, English target, are borrowed). The remoter history of the cognates is obscure.