Client-server system is a distributed system in which a server, such as mainframe, stores commonly used data and programs. The client, usually a PC or a work-station, asks the server for data and programs.
Newton’s Telecom Dictionary defines C/S technology as follows:
A form of shared, or distributed, computing in which tasks and computing power are split between servers and clients. Servers store and process data common to users across the enterprise; these data can then be accessed by client systems for individual processing requirements.