釉薬 (shinjitai kanji, kyūjitai kanji 釉藥, hiragana うわぐすり, romaji uwagusuri)
Originally a compound of 上 (uwa, “over, on top of”, ancient combining form of modern ue) + 薬 (kusuri, “a chemical, a substance with mystical properties”). The kusuri changes to gusuri as an instance of rendaku (連濁).
