Definition of mass action in English:

mass action

noun

  • 1Chemistry
    The effect which the concentration of a reactant has on the rate of a chemical reaction; especially in "law of mass action" noun the principle that the rate of a reaction at equilibrium is proportional to the concentrations or activities of the reactants.

  • 2The action of a mass of people.

Origin

Late 19th century; earliest use found in Journal of the Chemical Society.