Republic has come to mean a society where there is no hereditary or appointed monarch or emperor as head of state. The system of monarchy contrasts with a republic. Republics vary widely in their ideology and composition, though the most common definition of a republic is a state without a monarch. Republic derives from the original Latin res publica which means ‘things public’, those things that are connected to ruling the public realm. In the United States republic refers to representative democracy and republicanism refers to a specific ideology that is based on civic virtue. Originally Republic referred to a system of political rule where citizens, through representative institutions participated in government and exercised political power. Historically, republics contained an aristocratic class with hereditary titles and privileges.
The term 'republic' originated from the writers of the Renaissance such as Machiavelli as a descriptive term for states that were not monarchies. Constitutional monarchy in essence refers to a system in which the monarch acts as a non-party political head of state under the constitution. The word republic comes from the Latin term res publica, which literally means “public matter,” or “public affair” and was used to refer to the state as a whole. The term developed its modern meaning in reference to the constitution of the ancient Roman Republic.
In its narrower meaning the term Republic distinguishes Canada, Britain, Norway, Sweden, Denmark, the Netherlands, Thailand and other countries formally headed by monarchs, from France, Italy, Germany, the United States and many others where the head of state is a president either directly elected or appointed by an elected group. Parliamentary republic, Federal republic, Islamic Republic, Arab Republic, and Democratic Republic are some of the phrases used to describe and distinguish the type and nature of the various republics. A number of states of the classical era that are today by convention called republics includes the states of Ancient Greece such as Athens and Sparta and the Roman Republic.