glaze of porcelain

釉 is composed of 釆 (separate) and 由 (reason). 釆 is the pictograph of grain kernels separating and falling from the stalk of a rice plant, conveying the idea of separation, while 由 depicts oil droplets congealing into fat, with the original meaning being oil or fat; thus 釉 conveys the idea of a glossy protective layer on ceramics that resembles oil and effectively prevents moisture from penetrating, thereby keeping the ceramic body separate from water—and means glaze.