separation of powers
The division of governmental authority into three branches of government — legislative, executive, and judicial — each with specified duties on which neither of the other branches can encroach; the constitutional doctrine of checks and balances by which the people are protected against tyranny. Cf. DIVISION OF POWERS. [Cases: Constitutional Law 50–80(4). C.J.S. Constitutional Law §§ 54, 58–59, 111–227, 441.]