a pump for transferring water or other fluids by the rotating action of its component parts, as by the meshing of vanes or screws.
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British Dictionary definitions for rotary pump
engineering a pump in which a liquid is displaced through a shaped stator by a shaped rotor
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012