稳定 (wěn dìng) is an adjective meaning 'stable' or 'steady', describing something that is firm, unchanging, balanced, or resistant to disruption. The first character 稳 (wěn) conveys security, calmness, and reliability — like a person standing firmly on both feet. The second character 定 (dìng) means 'to fix', 'to settle', or 'to establish', suggesting permanence and control. Together, they emphasize consistency over time: a stable economy, a steady heartbeat, or reliable behavior. It’s commonly used in formal and technical contexts — especially in medicine, economics, engineering, and social policy.

The word often appears in compound nouns (e.g., 稳定性 wěn dìng xìng 'stability') or as a predicate adjective after 是 or 很. It can also function as a verb in rare contexts ('to stabilize'), but as an adjective it’s far more frequent. Unlike colloquial terms like 平稳 (píng wěn), 稳定 carries a stronger sense of resilience against external shocks and is preferred when precision and seriousness are required.