"Coffin"- Basically your link to the VirtNet. It's a big black box, which is where your body spends your time in the VirtNet. It, for instance, gives your body nutrients when you eat in the VirtNet, or gives you momentary pain when you die. It makes you feel the sensations of the VirtNet. It's actually called a NerveBox, but a Coffin is more fun to say.
"The Sleep"- When a player is in the video game world.
"The Wake"- When a player is not in the video game world.
Tangent- An AI(Artificial Intelligence). They live life, just as people do, but they only live in the VirtNet. They cannot go into the real world.
VirtNet- The video game world.
VNS- VirtNet Security. They basically own the VirtNet. They program and maintain it, taking care of hackers and other such nuisances.
The Code- Basically self explanatory. It makes up the entire being of VirtNet; What you see, what you feel, what you taste, what you smell. Hackers manipulate the Code in order to do certain things.