Bundle versus Application Identifier

On the Project Chooser window the “identifier” is called “Application Identifier” but in the Build Settings, what I think is the same field, is called “Bundle Identifier”. Any reason there are 2 different names?

It’s the same thing.
Use reverse domain name format with a domain that is actually yours.

Web projects use it as a different things than desktop apps for OS X do

Application Identifier is the generic term