A hill is a landform that extends above the surrounding terrain. It often has a distinct summit, and is usually applied to peaks which are above elevation compared to the relative landmass, though not as prominent as mountains.

The distinction between a hill and a mountain is unclear and largely subjective, but a hill is universally considered to be not as tall, or as steep as a mountain. Geographers historically regarded mountains as hills greater than 1,000 feet (304.8 meters) above sea level, which formed the basis of the plot of the 1995 film The Englishman who Went up a Hill but Came down a Mountain. In contrast, hillwalkers have tended to regard mountains as peaks 2,000 feet (610 m) above sea level. The Oxford English Dictionary also suggests a limit of 2,000 feet (610 m) and Whittow states "Some authorities regard eminences above 600 m (1,969 ft) as mountains, those below being referred to as hills." Today, a mountain is usually defined in the UK and Ireland as any summit at least 2,000 feet or 610 meters high, while the official UK government's definition of a mountain is a summit of 600 meters (1,969 feet) or higher. Some definitions include a topographical prominence requirement, typically 100 feet (30.5 m) or 500 feet (152.4 m). In practice, mountains in Scotland are frequently referred to as "hills" no matter what their height, as reflected in names such as the Cuillin Hills and the Torridon Hills. In Wales, the distinction is more a term of land use and appearance and has nothing to do with height.