I'm looking for a simple definition of the concept of “client-server”
I'd like something similar to this definition of state.
... That "thing/information" that you need to remember is called "state".
Edit - This isn't a homework question (nor am I a student). My goal is to come up with a compact way of explaining REST to average developers. I didn't want to prejudice the response though.
client/server refers to a relationship between two networked computers in which one machine (the client) initiates a connection and makes requests of the other machine (the server), which in turn to fulfill those requests. Servers exist to provide a service which clients consume.
Also, have you checked the Wikipedia article on REST? The second paragraph gives a similar definition which may help:
REST-style architectures consist of clients and servers. Clients initiate requests to servers; servers process requests and return appropriate responses. Requests and responses are built around the transfer of representations of resources. A resource can be essentially any coherent and meaningful concept that may be addressed. A representation of a resource is typically a document that captures the current or intended state of a resource.
One possibility is something like:
A client-server scheme is one in which the consumer (client) and producer (server) of a resource are designed to communicate by passing messages (intelligible objects that can exist independently of the client and server).
From Wikipedia:
A server is a computer system that selectively shares its resources; a client is a computer or computer program that initiates contact with a server in order to make use of a resource.
Client/server describes the relationship between two computer programs in which one program, the client, makes a service request from another program, the server, which fulfills the request.
For more information see: What is a client/server?
My teacher said once something like this (somehow it wont dissapear from my head):
In the real world, businesses have clients. In the computer world, servers have clients. The "client-server" architecture is common in both local and wide area networks. For example, if an office has a server that stores the company's database on it, the other computers in the office that can access the database are "clients" of the server.
A server is a computer that does stuff for another computer. The other computer is called a client.
