WordReference Random House Learner's Dictionary of American English © 2026
os•mo•sis /ɑzˈmoʊsɪs, ɑs-/USA pronunciation
n. [uncountable]
WordReference Random House Unabridged Dictionary of American English © 2026- Biochemistry, Chemistrythe tendency of a fluid, usually water, to pass through a membrane, causing the concentrations of materials on either side of the membrane to become equal:Water seeps into the roots because of osmosis.
- a process of gradual absorption:to learn French by osmosis.
os•mo•sis
(oz mō′sis, os-),USA pronunciation n.
os•mot•ic
(oz mot′ik, os-),USA pronunciation adj.
os•mot′i•cal•ly, adv.
- Cell Biology, Chemistry[Physical Chem., Cell Biol.]
- 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.
- the diffusion of fluids through membranes or porous partitions. Cf. endosmosis, exosmosis.
- a subtle or gradual absorption or mingling:He never studies but seems to learn by osmosis.
- French, equivalent. to end- end-, ex- ex-2 + Greek ōsm(ós) push, thrust + French -ose -osis
- 1865–70; Latinized form of now obsolete osmose osmosis, extracted from endosmose endosmosis, exosmose exosmosis
'osmotic' also found in these entries (note: many are not synonyms or translations):
hypertonic
- hypotonic
- isotonic
- osmoregulation
- osmosis
- osmotic pressure
- electro-osmosis
- iso-osmotic
- isosmotic
- mannitol
- osmometry
- root pressure
- serum albumin
- solion