a broad,gently sloping rock surface at the base of a steeper slope,often covered with alluvium,formed primarily by erosion

• 山前侵蚀平原，麓原，一种由侵蚀引起的在另一陡的倾斜底面上的宽而缓缓倾斜的岩石层面，其上通常覆盖着冲积土