os·​mo·​sis | \ äz-ˈmō-səs How to pronounce osmosis (audio) , äs- \

Essential Meaning of osmosis

1 biology : the process that causes a liquid (especially water) to pass through the wall of a living cell
2 : an ability to learn and understand things gradually without much effort She seems to learn foreign languages by/through osmosis.

Full Definition of osmosis

1 : movement of a solvent (such as water) through a semipermeable membrane (as of a living cell) into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane
2 : a process of absorption or diffusion (see diffusion sense 3a) suggestive of the flow of osmotic action especially : a usually effortless often unconscious assimilation (see assimilation sense 4) learned a number of languages by osmosis — Roger Kimball

Examples of osmosis in a Sentence

She seems to learn foreign languages by osmosis.
Recent Examples on the Web Her hometown years also meant an appreciation for country and blues essentially through osmosis. Natalie Maher, Harper's BAZAAR, 8 Sep. 2021 Joy Lin, a career coach based in Los Angeles, says remote workers must be more direct about their career goals and accomplishments, since bosses aren’t just going to pick up on those things by osmosis from the next desk over. Rachel Feintzeig, WSJ, 12 July 2021 Save for some unavoidable internet osmosis, the DCEU had completely passed me by. Jacob Siegal, BGR, 9 Aug. 2021 Pumps pushed the water across the barrier, making the process resemble a reversed form of natural osmosis. Jonathan Schifman, Popular Mechanics, 8 Aug. 2021 Some say the trading floor is the last bastion of Wall Street, where interns and young employees learn by osmosis. David Benoit, WSJ, 6 July 2021 Alternative music landed by way of osmosis in pop music. Andy Greene, Rolling Stone, 7 June 2021 East County’s recycling effort will use a reverse-osmosis purification process, mixing supplies at Lake Jennings before being treated again at a Helix Water District facility. Joshua Emerson Smith, San Diego Union-Tribune, 4 June 2021 Agencies don’t have the same opportunity as new employees to figure things out through osmosis. April Margulies, Forbes, 4 June 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'osmosis.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of osmosis

1863, in the meaning defined at sense 1

History and Etymology for osmosis

earlier osmose in same sense + -osis, after endosmosis, exosmosis; osmose generalized from endosmose "passage through a membrane from a region of lower to a region of higher concentration" and exosmose "passage through a membrane from a region of higher to a region of lower concentration" (later endosmosis, exosmosis), both borrowed from French, from end- end-, ex- ex- entry 2 + -osmose, from Greek ōsmós "push, thrust" (from ōthéō, ōtheîn "to push, thrust" + -(s)mos, resultative noun suffix) + French -ose -osis; ōthéō, ōtheîn probably going back to Indo-European *h2u̯odhh1-, iterative derivative of *h2u̯edhh1- "thrust," whence also Sanskrit ávadhīt "(s/he) has struck, has slain"

Note: The terms endosmose and exosmose were introduced by the French physician and physiologist Henri Dutrochet (1776-1847) in L'agent immédiat du mouvement vital dévoilé dans sa nature et dans son mode d'action, chez les végétaux et chez les animaux (Paris, 1826), p. 126: "Ainsi, lorsque c'est le plus dense des deux fluides qui est dans la cavité, l'eau y est introduite par l'action que j'ai nommée endosmose; lorsqu'au contraire c'est le plus dense des deux fluides qui est hors de la cavité, le fluide le moins dense, qui est au dedans, est poussé au dehors par une action inverse que je nommerai exosmose.[footnote] (1) Mot dérivé de ἐξ, dehors, et de ωσμος, impulsion." ("Thus when the denser of the two fluids is inside the cavity, the water is drawn in by the action that I term endosmose; when on the contrary the denser of the two fluids is outside the cavity, the less dense fluid, which is inside, is pushed outward by an inverse action that I term exosmose. (1) Word derived from ex, outside, and from ōsmos, impetus.") The reconstruction *h2u̯odhh1- is from R. Beekes, Etymological Dictionary of Greek (Brill, 2010), with Greek -ōth- presumed to be a contraction from *awoth-. Beekes rejects the suggestion by Chantraine (Dictionnaire étymologique de la langue grecque) that ōtheîn is the durative form of a verb *éthein allegedly seen in éthōn, a present participle of obscure meaning that occurs twice in the Iliad (and hence parallel, according to Chantraine, with the lengthened grade seen in pōléomai "go/come frequently" as against pélomai "become, take place").

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The first known use of osmosis was in 1863

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Last Updated

20 Sep 2021

Cite this Entry

“Osmosis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/osmosis. Accessed 23 Sep. 2021.

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More Definitions for osmosis


os·​mo·​sis | \ äs-ˈmō-səs How to pronounce osmosis (audio) , äz- \

Kids Definition of osmosis

: a passing of material and especially water through a membrane (as of a living cell) that will not allow all kinds of molecules to pass


os·​mo·​sis | \ äz-ˈmō-səs How to pronounce osmosis (audio) , äs- How to pronounce osmosis (audio) \
plural osmoses\ -​ˌsēz How to pronounce osmosis (audio) \

Medical Definition of osmosis

: movement of a solvent through a semipermeable membrane (as of a living cell) into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane

More from Merriam-Webster on osmosis

Nglish: Translation of osmosis for Spanish Speakers

Britannica.com: Encyclopedia article about osmosis


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