A remotely accessed PC is typically either located at home, at the office, or in a data center.
The user is located elsewhere, perhaps traveling, in a hotel room, at an airport, or in a different city.
The desktop virtualization approach can be contrasted with a traditional local PC desktop, where the user directly accesses the desktop operating system and all of its peripherals physically (using the local keyboard, mouse and video monitor hardware directly).
When a desktop is virtualized, its keyboard, mouse and video display (among other things) are typically redirected across a network via a desktop remoting protocol (such as RDP, ICA, VNC, etc). The network connection carrying this virtualized desktop information is known as a "desktop access session."
Read the rest of the article here