(biology, chemistry) diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal WordNet 3.0 & Open English WordNet

Osmosis is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential to a region of low water potential, in the direction that tends to equalize the solute concentrations on the two sides. Wikipedia

Movement of molecules through a membrane. Wikipedia Disambiguation

Movement of water towards to more concentrated compartment Wikidata

The passage of a solvent through a semipermeable membrane separating two solutions of different concentrations. OmegaWiki

The net movement of solvent molecules, usually water, from a region of lower solute concentration to a region of higher solute concentration through a partially permeable membrane. Wiktionary

Movement of molecules. Wiktionary (translation)