Define the term osmosis and what is osmotic pressure?

The process of flow of solvent from a solution through a semi-permeable membrane is called osmosis. The extra pressure that must be applied on the solution to stop the flow of solvent through the semi-permeable membrane is called osmotic pressure.
osmotic pressure is proportional to the molarity, C of the solution at a given temperature T. Thus:
P = C R T
Here P is the osmotic pressure and R is the gas constant.