Bones

When you die, there is a chance that the level as you left it is saved, to be reloaded in a later game. Such levels are known as bones levels, or simply bones.

Clues
How to tell if a level is a bones level:


 * Large concentration of different monsters
 * Few items on the floor
 * Presence of corpses, which are never randomly generated

Forensics
When encountering a bones level, it can be advantageous to know some details of the deceased, or at least the his or her class. For example, if you find a grave with a quarterstaff, a randomly named cloak, two spellbooks, and a magic marker, you can be fairly certain the corpse is that of an early wizard, from which you can deduce that the cloak is a cloak of magic resistance. This method comes with no guarantees, but the more "indicator items" you find, the more certain you can be.