Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration until equilibrium is reached. It is a passive process that requires no energy input.
Related terms
Osmosis: The diffusion of water molecules through a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
Concentration Gradient: The difference in the concentration of a substance between two areas, which drives diffusion.
Equilibrium: A state where the concentrations of substances are equal throughout a space, indicating that diffusion has balanced out differences