Translated from Latin, de facto means "in fact."
As a legal term, it is used to describe an entity or process that exists even though it wasn't created through – or didn't result from – legally or officially sanctioned methods.
Because it is such a broad term, it can be used in many contexts, but is most often used to describe certain businesses, governments or government leaders.
Legally, someone who takes control of a region or country by force and forms a new government without proper authorization has created a de facto government. Because they didn't come to power through legal means, the dictator will also be classified as a de facto leader. Any new rules and regulations established by the new government will also be regarded as de facto laws.
In a business context, a company that is incorporated without following all of the proper legal procedures is regarded as a de facto corporation.