I'm aware that Common Lisp has different binding environments for functions and variables, but I believe that it also has another binding environment for tagbody labels. Are there even more binding environments than this? If so, then is it fair to categorize Common Lisp as a Lisp-2?
These question are not meant as pedantry or bike-shedding, I only want to gain a better understanding of Common Lisp and hopefully get some pointers into where to dig deeper into its spec.
That would be namespaces, according to the HyperSpec:
(Point 1.)
Yes, there are more namespaces. I even remember a little snippet exposing most of them, but unfortunately, I can't find it anymore¹. It at least exposed variable, function, tag, and block namespaces, but maybe also types and declarations were included. There is also another SO answer that lists these namespaces.
In the comments to the above linked answer, Rainer Joswig agrees that the "general debate is about Lisp-1 against Lisp-n".
The "2" might be due to the relative importance of the distinction between value and function slots, or because the objects of the other namespaces aren't first-class objects. For example in the Gabriel/Pitman paper referenced in the other answer:
and:
¹) PAIP, p. 837: