A term used to describe the motion of the moving parts in a positive displacement pump.
One complete pump cycle is the path taken by the moving components from a starting point back to the starting point. For astick pump, the pump cycle consists of an upstroke, where fluid on the upper side of the pump piston is pushed out of the pump into the distribution system, and fluid on the lower side of the piston is drawn into the body of the pump, and a down stroke, where fluid passes from the lower to the upper side of the piston. One complete upstroke and down stroke of the pump is required to complete one pump cycle.
See also PEI/RP700.