A server is a computer that shares its resources such as peripheral devices and files with other computers, called clients, in a data network. It is possible for a computer to be the client and server at the same time. Moreover, it can be a program that receives queries from other applications and sends a response back.
Within the first category are many different groups, including data server, which mainly performs calculations, and file server mainly to store files.
A server’s purpose is to provide a number of clients access to computing power and / or data. A good example of this is a Web server that can provide a HTML -page available to all other machines connected to the world wide web.
The terms client and server comes from the 1970 terminal – and mainframe culture.