Secularism, also called Secularity, is the idea of something being not religious or not connected to a church or other religious organization. An example of this is the government, which is independent of any religion in many states. In some countries, such as Pakistan, England (though not the rest of the UK), Greece, Iran or Saudi Arabia, there is a state religion. In that case, the government follows the state religion. In contrast, India, South Africa or the United States have laws that religion and government should stay separate.
In a theocracy like the Vatican City and Iran, the priests of religion are the rulers of the country.