Authority is a noun that can be defined generally in a number of unique, yet related, ways. First, it can refer to a specific party that has the power or right to enforce decisions, laws, or rulings. Police officers, for example, are considered to be “authorities”. In many cases it can refer to the parties that actually have the power to make these decisions, laws, and rulings, and an example of authority in this sense can be seen in federal, state, and local judges. Authority can also refer to the power that may be assigned from one person to another to make specific decisions, such as in the example, “I have assigned to my lawyer the authority to make that decision.”In the area of project management, authority refers similarly to a person, or group or people, who have the power or right to make key decisions in the process of project planning and/or execution. These rights may include, but not necessarily be limited to, acts of application of project resources, making expenditures, and offering approvals.
This term is defined in the 3rd and the 4th edition of the PMBOK.