[mass noun]a soft, crumbly chalky rock, or the fertile loamy soil produced as it weathers 泥灰岩;白垩土 ■(亦作 malm brick)[count noun]a fine-quality brick made originally from malm, marl, or a similar chalky clay 白垩砖,灰砂砖
语源
Old English mealm-, of Germanic origin; related to meal