The terminal is just another means of access to the computer just like the monitor and its keyboard is. One could apply this same reasoning to a thin client and say that the client-server relationship is only for the transport of data. Thus a thin client is like a terminal. It has a GUI with a mouse that makes it seem like you are using a computer. You are, but that computer may be far away and have many other people using it at the same time you are.
Communication is over a high speed network cable or even over the Internet.
Some thin clients can, in addition, emulate a text terminal and have a serial port connector for that purpose. One even has a USB interface. This implies they should work with both MS Windows and Linux but early models may not be easy to use with Linux. They are true terminals since all the computing work is done by the server running Windows. This will be discussed in the next section.