There are several ways to make a distinction between pumps

There are several ways to make a distinction between pumps: 

1.)   Whether they are driven by a crankshaft or wobble plate
2.)   How many cylinders
3.)   Whether they are piston (cup) or plunger pumps
4.)   The method of crankcase lubrication
5.)   Whether they have a hollow or solid crankshaft. 

A crankshaft pump which has three cylinders (triplex plunger pump) uses a crankshaft similar to that of an automobile's crankshaft. The plunger is driven by the wobble plate pump that replaces the crankshaft with a cam (plate).