Diffusion and Osmosis

Diffusion is the net movement of particles from a region where they are at a higher concentration to region where they are at a lower concentration. ( Definition from notes )
Osmosis is a special type of diffusion, it is the diffusion of water molecules through a semipermeable membrane. So basically, if it is not water that is being diffused and there is no semipermeable membrane, then it is not diffusion.
This is one of those topics that I really had no idea existed until I was taught. Thus, when the teacher asked me to define the meaning of diffusion and osmosis, I just said that I did not know. However, once you understand what they mean, this topic gets a lot more easier.

This is an example of osmosis, a special kind of diffusion