A more thorough explanation:

Authority refers to the official permission or right to act on behalf of another person or institution. It can also refer to a person or institution that has power over another person.

For example, a police officer has the authority to enforce laws and maintain public order. A teacher has the authority to manage their classroom and make decisions about their students' education. A parent has the authority to make decisions for their child.

In the context of agency, authority is the power delegated by a principal to an agent. If someone takes an action on behalf of another without the authority to do so, the action is usually void. Actions carried out beyond or outside the scope of one’s authority are considered ultra vires (beyond the powers).

There are two types of authority: actual and implied. Actual authority is explicitly delegated by a principal to an agent. Implied authority is not expressly delegated, but it is inferred from the circumstances that the principal intends to confer this authority upon the agent.

For example, if a company hires an employee to manage their social media accounts, the employee has actual authority to post on behalf of the company. However, if the employee also responds to customer complaints via email, this may be considered implied authority because it is not explicitly stated in their job description but is necessary for the effective management of the social media accounts.