科学 (kēxué) means 'science' — the systematic study of the natural and physical world through observation, experimentation, and reasoning. The character 科 (kē) originally referred to a branch or category (as in an imperial examination division), and 学 (xué) means 'study' or 'learning'. Together, they denote organized, evidence-based knowledge — not just facts, but methods for discovering truth. In modern Chinese, 科学 is used broadly: from physics and biology to social sciences, and even as an adjective meaning 'scientific' or 'rational' (e.g., 科学的方法 — 'scientific method').

It frequently appears in compound words like 科学技术 (kēxué jìshù, 'science and technology'), 科学家 (kēxuéjiā, 'scientist'), and 科普 (kēpǔ, short for 科学普及 — 'popular science'). Unlike English 'science', which often excludes humanities, 科学 in Chinese can sometimes include disciplines like economics or linguistics when framed empirically — though natural sciences remain its core domain.