Dungeon, Explanation of:
A Dungeon is considered as any subterranean (underground) structure that has 3-20 rooms or chambers. Anything over 20 chambers is a considered as a Labyrinth.
Game Master:
When you create a Dungeon, you must develop 3+ chambers yet no more than 20, linked into one underground structure.
The first thing to do when creating a Dungeon is to determine the original purpose of its existence.
Use graph-paper to make the job easier if you need to. A dungeon takes about half an hour to create, so create one and set it aside for future use.