[ oz-moh-sis, os- ]
See synonyms for osmosis on Thesaurus.com
  1. Physical Chemistry, Cell Biology.

    • 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.: Compare endosmosis, exosmosis.

  2. a subtle or gradual absorption or mingling: He never studies but seems to learn by osmosis.

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Origin of osmosis

First recorded in 1865–70; Latinized form of obsolete osmose, extracted from endosmose endosmosis, exosmose exosmosis, from French, equivalent to end- end-, ex- ex-2 + Greek ōsm(ós) “a push, thrust” + French -ose -osis

Other words from osmosis

  • os·mot·ic [oz-mot-ik, os-], /ɒzˈmɒt ɪk, ɒs-/, adjective
  • os·mot·i·cal·ly, adverb
  • non·os·mot·ic, adjective
  • non·os·mot·i·cal·ly, adverb
  • un·os·mot·ic, adjective

Words Nearby osmosis

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use osmosis in a sentence

  • A reverse osmosis plant on an adjacent plot of land desalinates and purifies up to 1.25 million gallons of water daily.

  • And through basic cultural osmosis you learned its broad outlines: woman, travel, freeing of spirit, yoga.

    A Man's Guide to Eat Pray Love | Bryan Curtis | August 12, 2010 | THE DAILY BEAST
  • Any winery that possesses a reverse-osmosis machine—usually used to remove alcohol from wine—can create their own concentrates.

    The Great Wine Cover-up | Keith Wallace | August 18, 2009 | THE DAILY BEAST
  • In simple animals, as the sponge and hydra, no such organs are needed, the fluid food passing from cell to cell by osmosis.

    A Civic Biology | George William Hunter
  • No breathing organs are seen, because osmosis of oxygen and carbon dioxide may take place anywhere through the cell membrane.

    A Civic Biology | George William Hunter
  • The cell absorbs oxygen from the water by osmosis through its delicate membrane, giving up carbon dioxide in return.

    A Civic Biology | George William Hunter
  • Nourishment passes through them by a simple process of osmosis.

    Embryology | Gerald R. Leighton
  • Non-osmosis of non-digested foods, comparison between osmosable qualities of starch and grape sugar.

    A Civic Biology | George William Hunter

British Dictionary definitions for osmosis


/ (ɒzˈməʊsɪs, ɒs-) /

  1. the passage of a solvent through a semipermeable membrane from a less concentrated to a more concentrated solution until both solutions are of the same concentration

  2. diffusion through any membrane or porous barrier, as in dialysis

  1. gradual or unconscious assimilation or adoption, as of ideas

Origin of osmosis

C19: Latinized form from osmose (n), from Greek ōsmos push, thrust

Derived forms of osmosis

  • osmotic (ɒzˈmɒtɪk, ɒs-), adjective
  • osmotically, adverb

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for osmosis


[ ŏz-mōsĭs ]

  1. The movement of a solvent through a membrane separating two solutions of different concentrations. The solvent from the side of weaker concentration usually moves to the side of the stronger concentration, diluting it, until the concentrations of the solutions are equal on both sides of the membrane.♦ The pressure exerted by the molecules of the solvent on the membrane they pass through is called osmotic pressure. Osmotic pressure is the energy driving osmosis and is important for living organisms because it allows water and nutrients dissolved in water to pass through cell membranes.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for osmosis


[ (ahz-moh-sis, ahs-moh-sis) ]

The seeping of a fluid through a seemingly solid barrier, such as a cell wall or a rubber sheet. When the concentration of the fluid is the same on both sides of the barrier, osmosis stops.

Notes for osmosis

Informally, “osmosis” is the process by which information or concepts come to a person without conscious effort: “Living in Paris, he learned French slang by osmosis.”

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.