Right. The reason Common Lisp is called “common” is that it has a standard that allows anyone to build a lisp from scratch that will run any common lisp code es

Right. The reason Common Lisp is called “common” is that it has a standard that allows anyone to build a lisp from scratch that will run any common lisp code essentially completely unchanged (obviously you need to adjust a bit where you hit the OS, but even the file access methods are spec’ed). If you aren’t conformant you aren’t a Common Lisp - you could still be a lisp. Clojure is a lisp, just not a Common Lisp.