Pronunciation: (oz-mō'sis, os-),[key] —n. 1. Physical Chem.,Cell Biol. a. the tendency of a fluid, usually water, to pass through a semipermeable membrane into a solution where the solvent concentration is higher, thus equalizing the concentrations of materials on either side of the membrane.
b. the diffusion of fluids through membranes or porous partitions. Cf. endosmosis, exosmosis. 2. a subtle or gradual absorption or mingling: He never studies but seems to learn by osmosis.