for week of November 13, 2006:
Mud pump (noun) A pump used to circulate the drilling fluid (mud) on a drilling rig. The mud pump is usually a duplex or triplex positive displacement pump (piston pump) with two or three cylinders, whose pistons travel in replaceable liners and are driven by a crankshaft actuated by the rig engine. For some special applications, centrifugal-type pumps may also be used as mud pumps. Also termed slush pump.