A republic (from Latin res publica 'public affair') is a state in which political power rests with the public and their representatives, in contrast with a monarchy.Representation in a republic may or may not be freely elected by the general citizenry. In many historical republics, representation has been based on personal status and the role of elections has been limited. This remains true today; among the 159 states that use the word "republic" in their official names as of 2017, and other states formally constituted as republics, are states that narrowly constrain both the right of representation and the process of election.
The term developed its modern meaning in reference to the constitution of the ancient Roman Republic, lasting from the overthrow of the kings in 509 BC to the establishment of the Empire in 27 BC. This constitution was characterized by a Senate composed of wealthy aristocrats wielding significant influence; several popular assemblies of all free citizens, possessing the power to elect magistrates and pass laws; and a series of magistracies with varying types of civil and political authority.
Most often a republic is a single sovereign state, but there are also subnational state entities that are referred to as republics, or that have governments that are described as republican in nature.