Osmosis is the phenomenon of movement of solvent particles, in general water, from a region of lower solute concentration to a region of higher solute concentration. Diffusion, in the other hand, is the movement of solutes from a region of higher solute concentration to a region of lower solute concentration. One can consider osmosis as movement of water (solvent) and diffusion as movement of solutes, both concentration gradient-driven.   _{Your Comment}