A build system is a set of tools and processes that automate the creation of software applications. It compiles source code, links libraries, and packages the final product, ensuring that all components work together correctly. Common build systems include Make, Gradle, and Maven, each designed to streamline the development process. Build systems help developers manage dependencies, track changes, and optimize performance. By automating repetitive tasks, they reduce the risk of human error and save time, allowing developers to focus on writing code. This efficiency is crucial in modern software development, where projects can be complex and involve multiple contributors.