term:

Separation Of Powers

separation of powers

1 : the constitutional allocation of the legislative, executive, and judicial powers among the three branches of government
2 : the doctrine under which the legislative, executive, and judicial branches of government are not to infringe upon each other's constitutionally vested powers see also nondelegation doctrine

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.