Osmosis is a special form of diffusion.
Diffusion is the general movement of particles from a high to lower concentration.
Osmosis refers to the diffusion of water only, across a membrane.
Osmosis is the diffusion of water molecules, from a region where they are in higher concentration such as a dilute solution or pure water, to a region where they are in lower concentration such as a concentrated solution.
This movement of water via osmosis, happens across living cells, in the human body and in plants.
Let's try a few questions about osmosis and diffusion.