Compiler design is the process of creating a program, known as a compiler, that translates high-level programming languages into machine code, which can be executed by a computer's hardware. This involves several stages, including lexical analysis, syntax analysis, semantic analysis, optimization, and code generation. Each stage plays a crucial role in ensuring that the final output is efficient and error-free. The design of a compiler requires a deep understanding of both the source language and the target machine architecture. Compiler designers must also consider various factors such as performance, portability, and maintainability. By optimizing the translation process, compilers help developers write code more easily while ensuring that it runs efficiently on different systems.