vitreous
adj. US //ˈvɪtɹiəs// UK //vˈɪtɹiəs// vit·re·ous
From Middle French vitreux, from Latin vitreus (“glassy, transparent”), from vitrum (“glass”). The terms vitreous (positive) and resinous (negative) electricity were coined in 1733 by Charles François de Cisternay du Fay, who studied the different behaviour of glass and resin when rubbed with silk and fur, respectively.