The word republic can be traced all the way back to the Latin respublica, which referred to “the common weal, a commonwealth, state, republic”, in turn emerging from ‘res’, meaning ‘affair, matter, thing’ and ‘publica’, the feminine form of publicus or ‘public’.

The term originates from the Latin translation of the Greek word politeia, meaning a form of government, polity, or regime. Plato’s famous book on politics, Politeia, was translated in English as The Republic.

The idea was that a republic consisted of a state governed in the public interest, and so a Republic became the term for a form of government in which a state is ruled by representatives of the citizens as a whole.

Modern republics are founded on the idea that sovereignty rests with the people, which is also the core idea of a democracy, though the terms are not strictly synonymous. The word republic refers to a form of government whereas democracy is the political philosophy that determines how that government is run.

A republic, in other words, is the system of government that allows a country to be democratic. Another key difference relates to the identity of the head of state: one can be a democracy under a hereditary constitutional monarch, as Britain is, but in that case one is not a republic.

It is true, however, that because citizens govern their state through elected representatives, modern representative democracies are by and large republics. The key idea remains that a republic is a system of government where the power rests with a nation’s citizens, and not with its rulers. Today, 159 of the world’s 206 countries use the word ‘republic’ as part of their official names.

Practically speaking, however, the category of republic can encompass not only democratic states but also oligarchies, aristocracies, and tyrannies — most totalitarian one-party and communist states call themselves republics. (Just think of the Democratic People’s Republic of Korea — three falsehoods in one name!)

Still, in classical political theory, such states should be excluded from the definition of republics, because their object is not the common public good but the private benefit of a limited number of individuals and the subjugation of the citizenry, even if they pretend otherwise.

The term ‘republic’ evolved in contradiction to the monarchical and absolutist systems prevalent during the 17th and 18th centuries, when the growing resistance to such regimes manifested itself in a series of wars and revolutions, from the Eighty Years’ War (1568-1648) to the American Revolution (1765-1783) and the French Revolution (1789-1799). Shaped by those events, the term republic came to designate a form of government in which the leader is periodically appointed under a constitution, usually after a process of election, in contrast to hereditary monarchies, where birth alone defined power.

The three defining characteristics of a republic are that it is a form of government where the power rests with the people, is exercised through representative government, and has an elected head of state.

While some ancient Indian states were republics, notably those of the Licchavis who ruled northern Bihar and lower Nepal in the 6th and 5th centuries BCE (around the Buddha’s time), the Mallas, centred in the city of Kusinagara, and the Vajji (or Vrijji) confederation, based in the city of Vaishali, the most powerful ancient republic was the Roman Republic that existed between 500 BCE and 27 BCE. Until it gave way to an Empire under the imperial monarchy of unelected Caesars, Rome was largely run as a republic with a constitutional government.

Following the overthrow in 509 BCE of the last Roman king, Lucius Tarquinius Superbus, the Roman Senate decided to institute a new type of government under which the country would be led by two elected consuls, chosen by legislative assemblies made up of male citizens of Rome; the consuls had equal power and would serve one-year terms. Over the next few centuries, the government of Rome developed a set of guidelines and principles that became the Roman Constitution, under which even the Roman Empire was governed till it collapsed in the 5th century CE.

In a constitutional republic, the government is limited by laws established by a formal constitution, which is generally secular in nature; the government is run by elected officials who are voted in by the whole population, and elected representatives write or amend its laws. A republic can choose to follow a Parliamentary system (as the Republic of India does) or a Presidential one (like the United States of America, which is a Republic though it does not formally use that word in its name). It can be a federal republic, like the United States, Germany, and India, whose constituent states also have the power to make their own laws and decisions, as long as those don’t conflict with laws and policies established for the entire country on the federal level. (Thus Article IV of the United States Constitution “guarantee[d] to every State in this Union a Republican form of Government”). Or it can be a theocratic republic, like Iran, which is governed primarily by religious law while having an elected head of state.

Early Indian republicanism can be traced back to the independent gana sanghas, which appear to have existed between the 6th and 4th centuries BCE. The Greek historian Diodorus, writing about India at the time of Alexander the Great’s invasion in 326 BCE (though he wrote two centuries later), recorded that independent and democratic republics existed in India. They seemed, however, to include a monarch or raja, and a deliberative assembly that met regularly and discussed all major state decisions.

The gana sanghas had full financial, administrative and judicial authority, and elected the raja, who therefore was not a hereditary monarch. The raja reported to the assembly and, in some states, was assisted by a council of other nobles.

The oldest Indian republics varied. The Licchavis had a primary governing body of 7,077 heads of the most important families in the republic, while the Shakyas, Koliyas and Mallas opened their assembly to the participation of all men, rich and poor. Villages had their own assemblies, under local chiefs called Gramakas. But despite the assemblies, it is not entirely clear whether the composition and participation were truly popular, and the unequal caste duties and privileges of the members might well have affected their roles in the state, whatever be the formal importance of the institutions. Still, in the absence of hereditary monarchs with absolute powers, these states allow India to claim a standing equal to that of ancient Greece or Rome in the evolutionary history of the republic.