基本 (jīběn) is an adjective meaning 'basic' or 'fundamental'—it describes something essential, foundational, or indispensable to a larger system or concept. The character 基 (jī) means 'foundation' or 'base', while 本 (běn) means 'root', 'origin', or 'source'. Together, they reinforce the idea of something that forms the core or starting point of understanding, skill, or structure. It often appears before nouns (e.g., 基本知识 jīběn zhīshi — 'basic knowledge') or in predicate positions with 是 (shì) or 很 (hěn).

This word is widely used in educational, professional, and everyday contexts—for instance, when describing required skills ('basic computer skills'), essential needs ('basic living necessities'), or minimum standards ('basic requirements'). It carries a neutral, formal-to-semi-formal register and is common in textbooks, instructions, official documents, and spoken explanations about essentials.