Dam, n.
 1. A barrier to prevent the flow of a liquid; esp., a bank of earth, or wall of any kind, as of masonry or wood, built across a water course, to confine and keep back flowing water.
 2. Metal. A firebrick wall, or a stone, which forms the front of the hearth of a blast furnace.
 Dam plate Blast Furnace, an iron plate in front of the dam, to strengthen it.