Republic Act 10121, the Philippine Disaster Risk Reduction and Management Act of 2010, defines key terms related to disaster management, including disaster, mitigation, preparedness, response, risk, and vulnerability. It establishes a National Disaster Risk Reduction and Management Plan under the Office of Civil Defense and outlines the roles of various government departments in disaster prevention, preparedness, response, and rehabilitation. The act emphasizes a systematic approach to managing risks and enhancing community resilience to disasters.