osmosis \os*mo"sis\ ([o^]z*m[=o]"s[i^]s), n. [NL., fr. Gr.
   'wsmo`s, equiv. to 'w^sis impulse, fr. 'wqei^n to push.]
   (Chemical Physics)
   (a) The tendency in fluids to mix, or become equably
       diffused, when in contact. It was first observed between
       fluids of differing densities, and as taking place
       through a membrane or an intervening porous structure. An
       older term for the phenomenon was {Osmose}.

   Note: The more rapid flow from the thinner to the thicker
         fluid was then called {endosmosis} (formerly
         {endosmose}), and the opposite, slower current,
         {exosmosis} (formerly {exosmose}). Both are, however,
         results of the same force. Osmosis may be regarded as a
         form of molecular attraction, allied to that of
         adhesion. See also {osmotic pressure}.
   (b) The action produced by this tendency.
       
[1913 Webster]

Exosmosis \Ex`os*mo"sis\, n. [NL. See {Exo-}, and {Osmose}.]
   (Physics)
   See {Exosmose}.
   
[1913 Webster]