Res publica, a Latin term meaning 'public matter' or 'the public thing,' refers to the political system and governance of the Roman Republic, emphasizing the role of citizens in political affairs. This concept underlines the importance of civic participation and the idea that power is held by the people rather than a single ruler. The res publica set the foundation for a mixed government structure combining elements of democracy, aristocracy, and monarchy, which influenced future political thought and systems.