X terminal
A display with a built-in X server and nothing else: the programs ran on a Unix box in the machine room.
In X11 the server does the drawing and the client is the program, so building a device that was nothing but a server was an obvious move. Network Computing Devices, founded in 1987, made a business of it, and HP, Tektronix, IBM and DEC followed. An X terminal had a CPU, memory, graphics and a network card but usually no disk. It pulled its software over the network at boot, then asked a central host for a login via XDM.
For a university or an engineering department the maths was easy: one big server and thirty cheap displays instead of thirty workstations to upgrade one at a time. PCs running X server software took over in the late 1990s. The idea came back later, with new protocols, under the name thin client.