Backend development refers to the server-side aspect of software development, focusing on databases, scripting, and the architecture that powers applications. It involves creating the logic and functionality that enables users to interact with a website or app, managing requests, and ensuring seamless data exchange between the frontend and backend. Developers in this field work with programming languages such as Java, Python, Ruby, and PHP, and utilize frameworks and tools like Node.js, Django, and Ruby on Rails to build robust, secure, and efficient server infrastructure. Their work ensures that applications perform well, can scale, and remain secure, supporting a wide range of functionalities and user interactions.