Some languages that have CONS cells: Common Lisp, Emacs Lisp, Scheme, Dylan, Maclisp, Interlisp, AutoLisp, Lisp Machine Lisp, EuLisp, ISLisp, *Lisp, LeLisp, Lisp 1.5.
Some languages that don't have CONS cells: Clojure, Janet, Julia, R.
Of course, that is only one attribute, and may not be the most important one, but it's an interesting separating line.
If you describe each language by a set of language feature attributes, you can perform some easy computations (e.g., Jaccard distance, or some clustering) to get more clue about how related these languages really are. I think Janet wouldn't fare so bad in relation to obvious Lisps, so I'm not strongly opposed to calling it a Lisp.
Some languages that don't have CONS cells: Clojure, Janet, Julia, R.
Of course, that is only one attribute, and may not be the most important one, but it's an interesting separating line.
If you describe each language by a set of language feature attributes, you can perform some easy computations (e.g., Jaccard distance, or some clustering) to get more clue about how related these languages really are. I think Janet wouldn't fare so bad in relation to obvious Lisps, so I'm not strongly opposed to calling it a Lisp.