The Head of Government of any country is usually defined as the person within the government who heads up the cabinet of ministers responsible for administration responsible for various departments of the government.
There are many different power distributions, determining just how important the Head of Government is.
In monarchies, the King or Queen is the absolute ruler, and all other political power is derived from him/her. Most often in practice however the monarch is a figurehead, and the duties of the Head of State, either the monarch themselves, or their representative in the country, such as a Governor General, are largely ceremonial. The person who really runs the country is the Head of Government, usually an elected official known as the Prime Minister. Some examples of countries with this power structure include:
There are also some countries where the monarch does serve as the Head of Government. One example is Saudi Arabia.
Then there are countries where the power is roughly split between the Head of State and the Head of Government. Some examples are:
Some countries have the Head of Government as the real decision maker. The Head of State may be mostly ceremonial, or perhaps just having less power than the Head of Government. Some examples include:
In many countries, the Head of State is more powerful than the Head of Government. It may be that the Head of Government is little more than a figurehead, perhaps appointed by the Head of State. Or they could be something along the lines of the head bureaucrat, responsible for running the country smoothly.
Some governments are run a bit simpler. The Head of State and the Head of Government is the same person. Examples include:
And then of course there are the countries that have leaders who happened to be in charge of the military when it took over, and don't really have any official title such as President or Chancellor. General usually works. Examples are:
And the great theocracies. The guys who are the Head of State are religious leaders. The Head of Government is representing them. Like:
I obtained most of this information off the American CIA website at www.cia.gov . If anything looks incorrect, feel free to drop me a /msg.