保障 (bǎo zhàng) emphasizes safeguarding or securing something (e.g., rights, safety, livelihood) through systemic or legal measures, often as a noun meaning 'security'. It is more formal and institutional than 保证 (bǎo zhèng, a personal promise or assurance) and broader than 确保 (què bǎo, to ensure a specific outcome). As a noun, it refers to a protective guarantee (e.g., 社会保障 social security).