noun
(chiefly derogatory) A person who lives at, lived at, or was raised by someone at a low altitude or from any city. A person not raised in or by someone directly from high mountain areas. (used by those who were born, raised, and are still living in higher altitude non-city or city like areas).
(physics) An inhabitant of or observer in a universe with two spatial dimensions.
(cycling) A flatland BMX rider.