A dale is a valley, a wide, open area that stretches between hills. Some dales have rivers or streams flowing through them, while others are covered in grasses or other plants.
When a geologist describes something as a dale or a valley, it is typically a low area that's longer than it is wide, and bordered on at least two sides by hills or mountains. Dales with rivers are often called "vales," while a very small dale is sometimes called a "hollow," pronounced "holler" in rural Appalachia. Dale comes from the Old English word for "valley," dæl.