Furthermore, the common term is "layer."
I agree, Justin, the word "level" seemed goofy to me. I guess I might have just learned the nomenclature from a weirdo, but the jargon I use to describe these types of parts of an application is "presentation layer" = web GUI, "application layer" = processing of users' intentions to SQL, and database layer is SQL [& friends]. "Layer" is understood as neutral to both web developers & real programmers [kidding!] to refer to different parts of a project involving 2+ languages, 1+ for the user and 1+ for the server, and is typically used in exactly the same context as what's-his-name used "levels." I don't see what that term adds, and I had the same reaction, because there is already a more common term for that, which does not have hierarchical implications.
