Which feature on a map signifies an area of lower ground surrounded by higher terrain?

The term used to describe an area of lower ground that is surrounded by higher terrain is "depression." In geographical terms, a depression is a landform that represents a dip or low point in the landscape, which can occur in various forms, such as basins or sinkholes. Depressions are identified on maps using contour lines that are closely spaced and arc to indicate the lower elevation relative to the surrounding higher terrain.

This concept can be visualized with topographic maps, where contour lines circle around the lower elevation, indicating that the land rises as you move away from the depression. Understanding this feature is crucial for terrain analysis, navigational exercises, and assessing potential weather patterns that could occur in lower lying areas.

In contrast to the other terms, a plain is characterized by relatively flat terrain and is not necessarily lower than the surroundings; a plateau represents an elevated flat area, and a summit denotes the highest point of a hill or mountain. Each of these terms describes different types of landforms, which is why depression is the most appropriate answer to indicate a lower area encircled by higher ground.