What is a Dry Sump, and what is a Wet Sump?

The difference between a Wet Sump and Dry Sump oil system is that a Wet Sump is what you have in your car. The oil pools at the bottom of a pan and a pump moves the oil from pool all the way through the engine. A dry sump makes the oil return to a reservoir by scavenger pumps. Oil gets pumped to the engine bearings by a pressure pump. This system has a dual oil pumps.