Hi volume oil pump vs standard volume pump

Ottmundr said
There is no such thing as suction, fluids do not have tensile strength. All we have to help us move fluids is pressure and inertia.

I would think that a negative pressure in a tube would be called suction. Pardon my stupidity.
The definition of suction: the process of reducing air pressure by removing air or liquid from an enclosed space, or the force created by this reduction that causes two surfaces to stick together: