The separation of powers is a model for the governance of a state. Under this model, a state's government is divided into branches, each with separate and independent powers and areas of responsibility so that the powers of one branch are not in conflict with the powers associated with the other branches. The typical division is into three branches: a legislature, an executive, and a judiciary, which is the trias politica model. It can be contrasted with the fusion of powers in some parliamentary systems where the executive and legislative branches overlap.

Separation of powers, therefore, refers to the division of responsibilities into distinct branches to limit any one branch from exercising the core functions of another. The intent of separation of powers is to prevent the concentration of unchecked power and to provide for checks and balances to avoid autocracy or inefficiencies.

The separation of powers model is often imprecisely and metonymically used interchangeably with the trias politica principle. While the trias politica is a common type of this form, it is not its only type.

- extracted from Separation of Powers, Wikipedia as on 24th September 2018