Definition of: osmosis

(oz·mō′sis, os-) noun
1. The diffusion of two miscible solutions through a semipermeable membrane in such a manner as to equalize their concentration: it is one of the essential processes of living matter, especially in its cellular forms: also called diosmosis. Also os′mose. Compare ENDOSMOSIS, EXOSMOSIS.
2. Colloq. A process resembling diffusion and marked especially by the absence of directed effort: Living in Paris, he learned French by osmosis. [Earlier osmose <-osmose (as in endosmose, exosmose) <Gk. ōsmos a thrust, push]
—os·mot·ic (oz·mot′ik, os-) adjective
—os·mot′i·cal·ly adverb