Server-side development refers to the process of creating and maintaining the back-end logic and functionality that drives web applications. This involves developing and managing the server-side components of an application, such as servers, databases, APIs, and web services. Server-side development requires specialized skills in programming languages, such as PHP, Java, Ruby on Rails, Python, and Node.js, as well as experience in server management and database administration. Skilled server-side developers are essential for building scalable, secure, and efficient web applications that can handle high volumes of user traffic and data.