Authority delegated by the principal, which clearly sets forth in exact, plain, direct and well-defined limits those acts and duties, which the agent is empowered to perform on behalf of the principal, e.g. an exclusive listing.
An employee who is hired by agreement (oral or written) is an agent and has been given express authority to act on behalf of the business. That authority, however, may be limited; an express contract specifies the limitations of an agent's authority.