1. (Science: chemical) a contrivance, turning on a vertical axis by a handle or winch, and giving a circular motion to the ore to be washed; a stirrer.
2. (Science: machinery) a tool with an indented head for shaping the head of a rivet.
3. In pile driving, a block interposed between the head of the pile and the ram of the driver.
4. A small truck with a single wide roller used for moving heavy beams, columns, etc, in bridge building.
5. A compact, narrow-gauge locomotive used for moving construction trains, switching, etc.