Definition of a "vault"?

[Oddysee]

As you may have guessed, I'm not talking about the Vaults branch. I would like to know what people mean by a "vault" which (as far as I can tell) can occur anywhere in the dungeon.

[Galefury]

A human-designed bit of dungeon. Opposed to the randomly generated parts. This includes entry vaults (where you enter the dungeon), branch ends, encompass vaults (that replace a whole dungeon level), vaults that can just spawn anywhere on the level, portal vaults (sewer, wizlab, etc.), and so on. You can check them out here.

[evilmike]

Normally when people speak of vaults, they are talking about pre-designed rooms or levels (which can nevertheless be highly randomized). This is the common definition and the one you should usually use.

Technically, the definition of vault is a bit broader... it includes things like special rooms (which are generated by Lua), placement of unique monsters, and even weirder things, like the colours of Zot levels and a guaranteed early bread ration. All of those things are placed as "vaults", and you'll find them if you follow Galefury's link.

I should also note that the stuff in dat/des/builder/layout.des are not vaults. These are actual level layouts.