The problem (which you are right to point out) is that only top-level defines are dynamically scoped. That's why my first example doesn't return a 3 and why the

The problem (which you are right to point out) is that only top-level defines are dynamically scoped. That's why my first example doesn't return a 3 and why the binding from a nested define statement disappears. The top-level defines do fit the description of "indefinite scope", since they can be accessed anywhere in the program (even before they are defined). I don't know of anyway to remove a top-level define without shadowing it with another top-level define, so it would seem that they also fit the definition of "dynamic extent". Nested defines are very strange, so I think it is understandable that they don't quite fit in with either CLTL's definitions or with the classical definition of static scoping.