Wall text art. Examples of famous defensive walls include the Great Wall of China and Hadrian's Wall. Walls have historically served defensive purposes, and the term "wall" originally referred to defensive walls and ramparts. How to use wall in a sentence. wall, structural element used to divide or enclose, and, in building construction, to form the periphery of a room or a building. 2. Extremely unconventional. Without foundation; ridiculous: an accusation that is really off the wall. 1. He sat on the wall in the sun. A wall of people or things is a mass of them formed in such a way that you cannot get through or past them: (Definition of wall from the Cambridge Academic Content Dictionary © Cambridge University Press) A wall is a long narrow vertical structure made of stone or brick that surrounds or divides an area of land. ihmaff evn fsukqwr eelp jahp oukiyxts tuymya wdcgk ebdfsl zfeqxm