Respondeat Superior

Latin for "let the master answer," a key doctrine in the law of agency, which provides that a principal (employer) is responsible for the actions of his/her/its agent (employee) in the "course of employment." 

Thus, an agent who signs an agreement to purchase goods for his employer in the name of the employer can create a binding contract between the seller and the employer. Another example: if a delivery truck driver negligently hits a child in the street, the company for which the driver works will be liable for the injuries.

   Source: http://legal-dictionary.thefreedictionary.com/Respondeat+superior