cauldron

甑 is composed of 曾 (once) and 瓦 (root tiles). 曾 is the original pictograph of a steamer pot, while 瓦 signifies earthenware or clay items. As 曾 developed derivative meanings over time (such as layering or indicating past actions), and because ancient steamer pots were predominantly made of fired clay, 甑 was formed by adding 瓦 to explicitly preserve and represent its original meaning—an earthenware food steamer.