| the force that a dissolved substance exerts on a semipermeable membrane, through which it cannot penetrate, when separated by it from pure solvent. |

| osmotic pressure n. The pressure exerted by the flow of water through a semipermeable membrane separating two solutions with different concentrations of solute. |
osmotic pressure n.
The pressure exerted by the flow of water through a semipermeable membrane separating two solutions with different concentrations of solute.