Servers are computer systems or programs that provide services, resources, or data to other computers, known as clients, in a network environment. The main role of a server is to respond to client requests and facilitate resource sharing, such as files, applications, or providing services like web hosting, email, or databases. Servers can be physical computers or virtual machines, and there are various types of servers, including web servers, file servers, database servers, and others, each designed for specific tasks in a networked environment.