Diffusion is the movement of solutes from a higher concentration to a lower concentration.
It is important not to confuse this with osmosis, which refers to the movement of water only (from a lower concentration solution to a higher concentration solution.)
Diffusion and osmosis almost always goes hand-in-hand. A good way to remember this is if you imagine mixing a powdered juice drink. Diffusion talks about the powder's movement while osmosis talks about the water's movement.
