what it mean by president rule ?

President's rule is imposed in a state by the center when there is break down of law and order.President's rule is also imposed when no single party in elections has gained majority and they are unable to come to an understanding to form a coalition government.President's rule is imposed by the center on States under article 356 of the constitution when there is a breakdown of law and order or the constitutional machinery has broken down.Under such conditions the president under the advise of the prime minister and his cabinet appoints a governor as the head of the State to carry on the State administration.