noun 다운로드 🔗공유 거친 사암 A form of sedimentary rock, similar to sandstone but coarser. Examples : "The climbing wall was made of rough gritstone, making it challenging to grip. " 암벽 등반 벽은 거친 사암으로 만들어져 잡기가 어려웠다. geology material AI와 채팅어휘 게임독해 연습