One major difference between osmosis and diffusion is that diffusion

The major difference between osmosis and diffusion is that diffusion does not need a semipermeable membrane, while osmosis does. Diffusion is the movement of particles from an area of high concentration to an area of low concentration, while osmosis is the movement of water molecules across a semipermeable membrane from an area of high water concentration to an area of low water concentration. Diffusion can take place in both liquid and gaseous mediums, and can be demonstrated experimentally.