A republic is a form of government that has no monarchy and no hereditary aristocracy. It originates from Rome. In 509 BC, the Romans overthrew the Roman Kingdom and established a republic, a government in which citizens elected representatives to rule on their behalf.
National sovereignty lies in the authority of the government, not in an emperor or monarch. The word republic comes from the Latin words res publica, meaning a "public thing". For example, the United States and India are republics. However, the United Kingdom and Canada are not republics since they have a monarch (King Charles III in both cases)
Countries with a king or other monarch and free elections is called a constitutional monarchy, not republics. A constitutional monarchy resembles a republic because the constitution has been amended to remove power from the monarch and install institutions conforming to a philosophy of republicanism. That includes the United Kingdom and the other Commonwealth realms, the Netherlands, Thailand, and countries in Scandinavia and elsewhere. What makes a republic different is that its laws are made and enforced without royal authority.
The head of state in a republic is generally a person who has been chosen by the citizens by direct election or by a group of elected representatives to act as the top representative of the people. In most republics, the head of state is called the president. In some countries, the president is elected and has a lot of political power. In others, the president does not hold much direct power but is important in the legal system for other reasons.
Sometimes, state is called a "republic" when its head is not called a "king". For example, the Roman Empire had an "emperor" and the Dutch Republic had a "stadholder", but they worked as hereditary monarchs.
Licchavi, in India, was an aristocratic state in the 6th and 5th centuries BCE and is nowadays sometimes called the first republic. The earliest republics that were much imitated later were Greek cities, for example democracy in Athens. The biggest difference from the other city-states was that people chose their leaders by voting or by lottery. Several Italian city-states during the Renaissance were ruled by a small group of aristocrats, and were called republics.
- "The Roman Republic [ushistory.org]". www.ushistory.org. Retrieved 2019-03-14.