Based on is a prepositional phrase meaning 'founded on,' 'derived from,' or 'taking as a foundation.' The character 基 (jī) means 'foundation' or 'base,' while 于 (yú) is a classical preposition meaning 'at,' 'in,' or 'on.' Together, 基于 literally conveys 'on the foundation of' — emphasizing that something (a decision, conclusion, method, or action) rests upon specific information, evidence, experience, or conditions. It is commonly used in formal, academic, professional, and written contexts — especially in reports, proposals, analyses, and instructions.

This phrase typically introduces the source, reason, or starting point for what follows — often preceding nouns or noun phrases like data, research, experience, observation, or policy. Unlike casual alternatives such as 根据 (gēnjù), 基于 carries a slightly more technical or structural nuance, suggesting an underlying conceptual or logical grounding rather than simple reference.