a depression in the ground surface, esp in limestone, where a surface stream disappears underground 落水洞; 尤指石灰石地面下陷,地表水消失于地下 (Also called (esp Brit) swallow hole)
noun [专属名词]污水坑;排水口;阴沟口
The sinkhole was caused by rains and an underground sewageflow. 这个塌方的污水池是由于雨水和地下污水流动造成的。