Term invented by Scarlet Jester on the Gaming Outpost as part of GENder Theory, and adopted by The Forge. Broadly speaking, this is the process of establishing fictional events interactively -- i.e. the central process of role-playing. The act of exploration creates a diegesis or Shared Imaginary Space. It can be subdivided into components. Scarlet Jester suggested three components: Character, Setting, and Situation. Ron Edwards suggests five: the previous three plus System and Color.

References:

• The Threefold Model
• GNS and Other Matters of Role-playing Theory