Is a “client server” the same thing as a server? I mean, without clients, what else does a server serve? Perhaps “client server” is the full, proper name? 
I should add, have you ever seen a “client server” in a rack with a “server” immediately above it? Can you explain this configuration? If it helps, the end-user (work stations) are in the same room…maybe it’s a space saver? I mean, the client’s PC stored below the true server…is how I am picturing this arrangement.
You sure it’s not “client-server” as a compound adjective, describing a system that has both clients and servers? Otherwise it seems slightly redundant. All servers have clients. Maybe they’re referring to a specific group of clients, such as customers instead of internal users, or machines that can only be clients (as opposed to machines that can do other things as well).
What Sunspace said, unless maybe you’re describing a machine room where servers belonging to two different businesses are located, and one company is a (business)client of the other - in which case someone might have labelled it as the client’s server.
(that’s a long shot, of course)
Client Server as a phrase is used to describe a computing architecture, where the work of computing and displaying information is split between a display/data entry system (the client) and the backend (the server). However, the term is used loosely and devices can labelled differently. For the X-Windows remote display system, the input/output system is called the X-Server (and runs on a client PC) and the application is the client (but this may be running remotely on a server or locally). In the Windows Terminal Services remote display system (a similar system to X-Windows), the input/output system is a client on a client PC, and the applications run on a Terminal Services Server.
As for a physical device being labelled a client server, this has no real meaning, unless it is in the context of the specific system setup. In other words, it is a jargon term that may or may not accurately describe the actual role of the system in question. It is probably a server (maybe a middleware or database server) that runs specific software accessed using a client on the workstations.
Si
It might help if you provided more information about the situation and who or what is calling a system a “client server”. As other posters have noted, generally client-server refers to a type of architecture, not a particular system.
People have addressed the technical definition, but as I remember it “client/server” was as much a marketing term as a technical one. In the 80s it became a popular way of distinguishing between the older mainframe/dumb terminal architecture and the newer systems with PCs or smart workstations acting as clients to mini- or microcomputer based servers. But really, terminals on a mainframe are clients too, and mainframes are servers. Even peer-to-peer systems are client/server, it’s just that both ends act as clients and servers to each other.
Hmm, this could explain it. Clients access specific software via workstations. It could be that the server “serves” the client server (as conventional), and the client server “serves” the workstations?
As others have explained, the term client/server describes an architecture, not a machine.
In a client/server setup, the user sits at a computer (the client) and accesses an application which is being run on a different computer (the server). All web sites and internet based applications are run this way. The client runs a web browser (Internet Explorer, Firefox, etc.) which sends and receives information from a remote computer (the server).
There are also non-internet based programs that use the client/server model, especially in corporate environments where the users’ computers (clients) run applications off of the company’s network (server).
This is different from single user applications, such as Word, where the entire application is installed and runs on a single computer.
There’s no such thing as a client server. You’ve got you clients, and you’ve got your servers. Much in the same way that there’s no such thing as a customer waiter.
It’s possible they mean that’s the server for the clients processes, as opposed to an internal facing server handing testing or the server handing development. Usually called production server obviously, but I wouldn’t be surprised if someone referred to it as the client server.
Ok, on a similar note…what is meant by “host” or “hosted”, in IT talk?
Again, it can be a nebulous term. A host can mean a system that is accessed remotely, usually with an interactive guest session.
Hosting (or the word host as a verb) usually refers to a system in the context of a shared facility. A web server may well be hosted in a facility with thousands of other web servers, with shared internet access and power. A single web site may be hosted with several other sites on a single server.
Si
It’s just called X, incidentally, but otherwise well-explained.
Note that there are variations in Client-Server architectures. While we’ve described a client hitting a server with an application, there are multi-tier architectures that divide some of the workload across different servers between presentation (user facing), application (where the logic occurs) and database (where the information is stored) servers.