Its word originates from the Latin cum (with) and statuere (establish). It is defined as the fundamental law of a State, established or accepted as a guide for its governance. It is also known as Magna Carta. The Constitution contains the laws or doctrines that establish the form of political organization of a State, and sets the limits and relations between its powers (which are generally the Legislative exercised by the parliament, congress or assembly; the Executive, exercised by the government; and the Judicial, by the judges). In addition, it establishes the rights and duties of citizens and rulers, as well as the organization of the territory in municipalities, provinces and other divisions, such as autonomous communities (in the case of Spain) or states (in the case of Venezuela).

The Constitution can be modified in order to improve or update it, the Constitutional Court is usually in charge of deciding which laws are in accordance with the Constitution and which are not, and if it is an important change, citizens are consulted or to the people through a referendum or constitutional reform, where by voting they express whether or not they agree with the change. This act is carried out in democratic countries, since in countries with a dictatorship, their Constitution is imposed by the dictator, who does not consult the Parliament or the citizens.

Most countries have a written Constitution, while others do not, such as Great Britain, its Constitution is represented in numerous documents and customary law (uses and customs).

Similarly, the word constitution has another meaning; it is the way in which something is composed or the way in which its constituent elements are structured. Example: “IYour rugby players have a strong and robust constitution”.