Le Chatelier's principle

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• noun chemistry A principle that states that if a chemical system at equilibrium experiences a change in concentration, temperature, or total pressure, the equilibrium will shift in order to minimize that change.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the principle that if any change is imposed on a system that is in equilibrium then the system tends to adjust to a new equilibrium counteracting the change