‘依据’ (jù yī) is a formal noun meaning ‘basis,’ ‘grounds,’ or ‘evidence’—something that supports a decision, judgment, claim, or action. Though the characters appear in reverse order in pinyin (yī jù), the word is always written and read as 依据. ‘依’ means ‘to rely on’ or ‘to follow,’ while ‘据’ means ‘evidence’ or ‘a factual basis.’ Together, they convey the idea of relying on something concrete and authoritative to justify a position or course of action.

This word is common in academic, legal, medical, and administrative contexts—for example, citing research findings as the basis for a treatment plan, or referencing regulations as the grounds for an official decision. It often follows prepositions like ‘根据’ (gēn jù, ‘according to’) or appears after verbs like ‘提供’ (tígōng, ‘to provide’) or ‘作为’ (zuòwéi, ‘to serve as’). While it can occasionally function adverbially in fixed phrases, its core use is as a noun denoting a foundational reference point.