What is the definition of a valley in geographic terms?

A valley, in geographic terms, is defined as a low area of land that is often surrounded by higher ground, typically characterized by its shape reflected in contour lines. The description of a valley as a "stretched groove of land marked by U- or V-shaped contour lines" captures the essential features that distinguish it from other landforms. The U-shape usually indicates formation from glacial activity, while a V-shape generally indicates that the valley has been carved by river erosion. This highlights the natural processes that shape valleys, making them distinctive as they feature low elevations relative to their surroundings.

Other descriptions, such as a sloping line of high ground or a vertical slope with touching contour lines, refer to other geographical features. High ground would more accurately describe a ridge or hill, and a vertical slope characterized by touching contour lines points to cliffs or steep rock faces. A less developed valley is somewhat vague and does not provide a clear, universally accepted definition of what constitutes a valley, which is fundamentally about the formation and shape of land.

Understanding the correct definition of a valley helps in recognizing various geographical formations and the processes that create them.