Ma*drier" (?), n. [F., from Sp. madero, or Pg. madeiro, fr. Sp. madera wood for building, timber, Pg. madeira, L. materia stuff, materials, lumber. See Matter.] A thick plank, used for several mechanical purposes; especially: (a) A plank to receive the mouth of a petard, with which it is applied to anything intended to be broken down. (b) A plank or beam used for supporting the earth in mines or fortifications.