Yes at the very basic level that is correct.
a little more info:
By default, the server listens on TCP port 3389 and UDP port 3389. Microsoft currently refers to their official RDP client software as Remote Desktop Connection, formerly "Terminal Services Client". The protocol is an extension of the ITU-T T.128 application sharing protocol.
also RDP or mstsc is available on all windows operating systems to connect to another server, but to allow a system/server to be remotely connected to you must have and os that supports it and rights on said system. Microsoft Server 2003 and later will be no problem. Enterprise editions of windows are no issue. Home versions and non pro versions are not supported for remote connectivity.
For rights you need remote operator access or higher (administrator for example). When you connect, copy and paste between the client and host are allowed. Depending on security controls, you may also share a drive (like your local hard drive) and printers.
There is a lot more info on Microsoft's site and Wikipedia but the above covers the basics.
It also is common practice to use a different port for rdp in an enterprise environment to provide enhanced security. Port scanning can allow someone to find the default port and then leverage that to infect the system. (see recent samba virus that made the news the last month).
Hope that answers your questions. that covers the basics. If you have any more questions, feel free to ask. If I have time, I will try and answer them this evening.