X Windows Protocol - A network terminal standard developed at MIT that enables a user to run and display multiple network applications at the same time.
X2 - This is US Robotics 56 Kbps modem standard. It is faster than a 28.8 modem, and many ISPs support it.
XGA - This started out as IBM's term for a computer monitor resolution standard of 1024 x 768 pixels and 16-bit color. Laptop makers often mention that their screens are XGA, meaning that they support that resolution.
