While hiking, we accidentally stepped into a deep pothole formed by rainwater erosion.

pothole 是由 pot（锅、壶）和 hole（洞）组成的复合词，字面意思是"锅形的洞"。这个词特指路面或地面上因雨水侵蚀而形成的坑洞，形状通常像锅一样凹陷。