Summary

Diffusion is the movement of particles from an area of high concentration to an area of low concentration until the concentration is evenly distributed.

Osmosis is the movement of solvent molecules from a dilute solution to a concentrated solution across a semi-permeable membrane.

Diffusion and osmosis involves the movement in living cells.

Concentration gradient is required for both movements.

Osmosis occurs only in liquid medium but diffusion occurs in both gas and liquid. Osmosis occurs through a semi-permeable membrane.