n. [wall, verb] The process of reinforcing the sides of a vertical shaft with tubbing or staves to prevent displacement sidewise by pressure of the earth. It is done either with planks or steel, or, in important and permanent workings, with brick.n. In billiards, same as bricole, 4.n. Walls collectively; materials for walls.n. In mining, the brick or stone lining of a shaft; steining.n. The act of boiling; a boiling.