The net movement of water into or out of the cell is driven by differences in
Osmotic pressure is a measurement of how strongly a solution will draw water into itself from an adjacent solution across a semi-permeable membrane.
Living cells have the potential of gaining or losing water from the surrounding extracellular fluid through osmosis. It is the difference in the solute concentration across a semi-permeable membrane that provides the driving force for osmosis. The overall water movement is possible only if the semi-permeable membrane is ready to accommodate this change in volume. As more water is drawn into the more concentrated solution, there's a build up in pressure leading to cessation (stopping) of osmosis.