Prerogative

An exclusive privilege. The special power or peculiar right possessed by an official by virtue of his or her office. In ENGLISH LAW, a discretionary power that exceeds and is unaffected by any other power; the special preeminence that the monarch has over and above all others, as a consequence of his or her sovereignty.

The term prerogative is occasionally used by writers of law to refer to the object over which royal powers are exercised, such as fiscal prerogatives, which are the revenues of the king or queen.