There is a basic rule: all languages carrying Lisp in their name implement much of the core of McCarthy's Lisp: Emacs Lisp, ISLISP (which is defined by an ISO

There is a basic rule: all languages carrying Lisp in their name implement much of the core of McCarthy's Lisp: Emacs Lisp, ISLISP (which is defined by an ISO standard) Standard Lisp, Common Lisp (which has an ANSI Standard), ... Languages in the wider Lisp family, which are more or less incompatible (Logo, Clojure, Dylan, ...) don't use Lisp in their name.