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. [ 1913 Webster ]