Preventing tyranny refers to the principles and measures taken to guard against the concentration of power in a single authority that could lead to oppression or authoritarianism. This concept is crucial in a democratic system where the aim is to protect individual rights and maintain a balance of power among different branches of government. Through mechanisms such as checks and balances, the separation of powers, and active civic participation, societies strive to prevent any one group from monopolizing power and infringing on freedoms.