'功能' (gōng néng) literally combines '功' (gōng), meaning 'work', 'effort', or 'achievement', and '能' (néng), meaning 'ability' or 'capacity'. Together, they form a noun meaning 'function' — the specific purpose, role, or activity that something is designed or naturally able to perform. It’s widely used in technical, medical, and everyday contexts, such as describing what a device does ('this app has many functions') or how a body system operates ('liver function'). Unlike the English word 'function', 功能 is almost never used as a verb in Chinese.

The term emphasizes practical utility rather than abstract mathematical or formal definitions. It appears frequently in product manuals, healthcare reports, software interfaces, and scientific discussions. While it can refer to biological roles (e.g., kidney function), it's not limited to living things — machines, apps, and even social institutions have 功能. It's a neutral, standard-register term suitable for both spoken and written Chinese.