Definitions

1. noun

A long, sinuous ridge or mound of glacial debris, often formed from a stream of meltwater that flowed beneath the ice during the last ice age.

“The tourists hiked along the esker, enjoying the scenic views of the surrounding countryside.”

2. noun

A long, narrow ridge of sand or other sediment, formed by a river or stream.

“The geologist studied the esker, noting its unique shape and composition.”