Wall  —n. 1 continuous vertical narrow structure of usu. Brick or stone, esp. Enclosing or dividing a space or supporting a roof. 2 thing like a wall, esp.: a a steep side of a mountain. B anat. The outermost layer or enclosing membrane etc. Of an organ etc. —v. 1 (esp. As walled adj.) Surround with a wall. 2 a (usu. Foll. By up, off) block (a space etc.) With a wall. B (foll. By up) enclose within a sealed space.  go to the wall be defeated or pushed aside. Off the wall us slang unorthodox. Up the wall colloq. Crazy or furious. Walls have ears beware of eavesdroppers.  wall-less adj. [latin vallum rampart]