世界 (shì jiè) literally combines 世 (shì), meaning 'generation' or 'era', and 界 (jiè), meaning 'boundary' or 'realm'. Together, they form the abstract concept of 'the entire earth and human society' — what English speakers call 'the world'. It refers to the planet Earth as a physical place, the global community of people, or the totality of human experience and knowledge.

This word is used broadly: in geography ('the world map'), science ('world climate'), culture ('world history'), and everyday expressions like 'in the world' (in the universe or among all things). Unlike the more poetic or literary term 宇宙 (yǔ zhòu, 'universe'), 世界 emphasizes the inhabited, social, and earthly dimension — it’s where people live, interact, and build civilizations. It appears frequently in compound words such as 世界第一 (shì jiè dì yī, 'world number one') and 世界观 (shì jiè guān, 'worldview').