An acid-base indicator which is colorless in acid solution, but turns pink to red as the solution becomes alkaline. It is used medicinally as a cathartic.
Mother-of-pearl
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The hard pearly internal layer of several kinds of shells, esp.of pearl oysters, river mussels, and the abalone shells; nacre. SeePearl.
Mother-of-pearl meaning & definition 1 of Mother-of-pearl.
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