The set of rules of a country is commonly referred to as its "laws" or "legal system." These laws are typically codified in a constitution, statutes, and regulations, which govern the behavior of individuals and institutions within the country. Additionally, the framework of these laws may be influenced by international treaties and customs. Together, they establish the legal standards and principles that guide a nation's governance and societal conduct.
Mayflower compact
The rules of a language is called its syntax.
The family that rules a country is called a "dynasty."
Protocol.
The constitution of a country is its highest law. It's a set of rules and principles according to which a country is governed.
The Declaration of Independence
Such a "set of rules" is called a "protocol". The protocol in this specific case is called HTTP.
colony
A colony
a banana
protocol
A small group that rules a country after taking it over by force is typically called a junta or a military dictatorship.