(1) A mathematical constant that describes the tendency of a large molecule to dissociate reversibly into smaller components.
(2) The equilibrium constant in a dissociation reaction.
Dissociation constant is a type of equilibrium constant that specifically involves the measure of the propensity of dissociation of a complex molecule into its subcomponents. An example of its application is to describe how tightly a ligand binds to a particular protein.
Also called: equilibrium dissociation constant, ionization constant.
Compare: association constant