trass
/træs/
📖 中文释义
- n. 火山灰
📘 English Definition（英文释义）
- n. A white to gray volcanic tufa, formed of decomposed
- trachytic cinders; -- sometimes used as a cement. Hence, a coarse sort
- of plaster or mortar, durable in water, and used to line cisterns and
- other reservoirs of water.