A type of DisklessWorkstation, often solid state (no moving parts), that handles input and output (keyboard, mouse and monitor), and offloads all the processing to a TerminalServer or Citrix server at the other end of a network.
Popularised by SunMicrosystems in the 1990s.
You can take a network of really old PCs, put a decent graphics card and a new screen on them, connect them to a single grunty machine, and breathe life back into the network for a comparitively low cost (think: save $2000 on each machine)
The LUG owns one of these (an NCD unti powered by Windows CE) that can be loaned out. See WlugLibrary for details.