A rebellion is when people refuse to obey orders and fight against authority. Those who do this are "rebels". They may be citizens of a country who try to take over the government by force because they do not trust the current system. Some rebels in history were slaves who fought back against their masters or against slavery in general. Leader of slave rebellions include Spartacus and Nat Turner.
An example would be the Zhou dynasty in China who made the rulers of other Chinese states that they captured live with their own families in the Zhou capital, Anyang. However, they failed to stop rebellion this way because it brought together groups of lords who might rebel under their control. The Zhou dynasty declined because other lords that were ruling parts of China rebelled.
Rebellion is a usual method of secession.