A governor is a leader of some kind. In some countries, the governor is the leader of a state or a province.
For example, in the United States, all 50 states have a governor elected by its own people. While the President is the leader of everyone in the United States, Governors are the leaders of the people living in or visiting their state. The governor is the executive for the state's administrative processes.
In Australia and Canada a governor represents the monarch in ceremonies. In many countries such as Pakistan a provincial governor is appointed by the central government acting as the ceremonial head of the provinces.