An Etymological Dictionary of the German Language/zugleich
zugleich, adv., ‘at the same time, together,’ ModHG. only, implying MidHG. *ze gelîche, ‘in the same manner’ (see gleich).
zugleich, adv., ‘at the same time, together,’ ModHG. only, implying MidHG. *ze gelîche, ‘in the same manner’ (see gleich).