An area of hilly land in the country. This is another of those slippery land words so common in Tolkien that I’ve always sort of glossed over with a general sense that it meant some sort of land but with no certainty as to the actual characteristics of the land. When capitalized, it is “a hilly or rolling region —used in names of various English geographic areas.”

The Lord of the Rings, page 429.

Before long they came to the borders of the Entwash, and there they met the other trail of which Eomer had spoken, coming down from the East out of the Wold.