In politics, authority (Latin auctoritas, used in Roman law as opposed to potestas and imperium) is often used interchangeably with the term "power". However, their meanings differ: while "power" refers to the ability to achieve certain ends, "authority" refers to the legitimacy, justification and right to exercise that power. For example, whilst a mob has the power to punish a criminal, such as through lynching, only the courts have the authority to order capital punishment.