Grit

I have often heard (and have likely made the comment myself) that older versions of D&D are "grittier" than newer versions.

But what makes a game "gritty"? Is it lethality? Is it strictly atmosphere?
Some adjectives I have heard to describe a "gritty" game: realism, lethal, dark, sacrifice.

A few things that I think make B/X a gritty game:
1. The fragile nature of the characters.
2. The roster of monsters. The number of giant versions of normal animals, dinosaurs and bugs keeps things "grounded"
3. The focus on resource management - it is tough to feel really heroic when you are worried that you might run out of torches and be lost in the dark.


Is White Plume Mountain gritty? It definitely is lethal.

Is Dark Sun gritty? I would say yes.

What do you think? What is "gritty"? What makes a game gritty?