PREROG'ATIVE, [Latin proerogativa, precedence in voting; proe, before, and rogo, to ask or demand.] An exclusive or peculiar privilege. A royal prerogative is that special pre-eminence which a king has over all other persons, and out of the course of the common law, in right of his regal dignity. It consists in the possession of certain rights which the king may exercise to the exclusion of all participation of his subjects; for when a right or privilege is held in common with the subject, it ceases to be a prerogative Thus the right of appointing embassadors, and of making peace and war, are, in Great Britain, royal prerogatives. The right of governing created beings is the prerogative of the Creator.

It is the prerogative of the house of peers in Great Britain to decide legal questions in the last resort. It is the prerogative of the house of commons to determine the validity of all elections of their own members. It is the prerogative of a father to govern his children. It is the prerogative of the understanding to judge and compare.

In the United States, it is the prerogative of the president, with the advice of the senate, to ratify treaties.