A wall is a structure and a surface that defines an area; carries a load; provides security, shelter, or soundproofing; or, is decorative. The term wall comes from Latin vallum meaning 'an earthen wall or rampart set with palisades, a row or line of stakes, a wall, a rampart, fortification' while the Latin word murus means a defensive stone wall. English uses the same word to mean an external wall and the internal sides of a room, but this is not universal. Many languages distinguish between the two. In German, some of this distinction can be seen between Wand and Mauer, in Spanish between pared and muro. Famous walls: Berlin Wall, Great Wall of China, Hadrian's Wall, Wailing wall. (Wikipedia)