Donnan equilibrium
noun
Don·nan equilibrium
| \ ˈdän-ən-
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Medical Definition of Donnan equilibrium
: the ionic equilibrium reached in a solution of an electrolyte whose ions are diffusible through a semipermeable membrane but are distributed unequally on the two sides of the membrane because of the presence of a nondiffusible colloidal ion (as a protein ion) on one side of the membrane