Osmosis only talks about water molecules
Diffusion talks everything other then the water molecules.
So,
Osmosis : water molecules travel from a region of a higher water potential to a region of lower water potential through a partially permeable membrane via osmosis
Diffusion : Travels from a region of higher concentration to a region of lower concentration through a partially permeable membrane via diffusion
We would not be able to live without it! It sustains life as we know it!
