A system of government that allows executive powers to be vested in one person

A system of government in which executive powers are vested in one person is the presidential system. In a presidential system, the president serves as both the head of state and the head of government, exercising executive authority as a single individual. The president is typically elected directly by the people and is not dependent on the legislature for their position.

This distinguishes the presidential system from other forms of government:

• In a parliamentary system (also called the cabinet system), executive power is collectively exercised by the cabinet, headed by a prime minister. The prime minister is not a sole repository of executive power but rather a "first among equals" within the cabinet. Executive authority is shared.
• A federal system describes how power is distributed between central and regional governments, not how executive power is structured. A federation can operate either a presidential or parliamentary system.
• The cabinet system is another name for the parliamentary system, where collective cabinet responsibility prevails rather than power vesting in a single individual.

The United States and Nigeria are examples of countries that practise the presidential system, where executive power is concentrated in one elected president.