模块 (mó kuài) literally combines 模 (mó, 'model' or 'pattern') and 块 (kuài, 'piece' or 'chunk'), suggesting a self-contained, reusable unit that fits into a larger system. In modern Chinese, it most commonly refers to a functional unit in software development — such as a code segment with specific responsibilities — or an independent learning unit in education, like a themed lesson block in a curriculum.

The word is widely used in technical, academic, and workplace contexts. Unlike native Chinese compounds, 模块 is a loanword adaptation from English 'module', retaining its conceptual precision. It implies modularity: each 模块 has clear boundaries, defined inputs/outputs, and can be developed, tested, or taught separately without affecting others. You’ll encounter it in phrases like '功能模块' (functional module), '教学模块' (teaching module), or '系统模块' (system module).