potash
/ˈpɒtæʃ/noun
mass noun
- an alkaline potassium compound, especially potassium carbonate or hydroxide钾碱（尤指碳酸钾, 氢氧化钾）, 木灰。
词源
early 17th cent.: from pot-ashes, from obsolete Dutch potasschen, originally obtained by leaching vegetable ashes and evaporating the solution in iron pots.