As names, car and cdr are great: short, and just the right visual distance apart. The only argument against them is that they're not mnemonic. But (a) more mnemonic names tend to be over-specific (not all cdrs are tails), and (b) after a week of using Lisp, car and cdr mean the two halves of a cons cell, and languages should be designed for people who've used them for more than a week.
I feel like this applies just as much (if not more so) to calling something the "contents of the address part of the register" or "contents of the decrement part of the register", especially when in actuality the "car" and "cdr" of a cons cell are implemented in a way that has nothing to do with an IBM 704.
> short, and just the right visual distance apart
Even shorter (and similar visual distance apart) would be cl and cr (for "cons left" and "cons right", i.e. the car and cdr, respectively). Or pl and pr if we swap "cons"/"cell" for "pair". Like car and cdr, these can be combined into other operations, like (cllllr foo) -> (cl (cl (cl (cl (cr foo))))). Heck, we could go even shorter with just "l" and "r". They're even kinda pronounceable ("cull", "curr", "cullullullullurr"). Literally all the upsides of "car" and "cdr" without any historical baggage.
Point being, if Bel is supposed to be a reconceptualization of Lisp, it feels really weird to not reconceptualize how we talk about cons cells and the contents thereof.
> after a week of using Lisp, car and cdr mean the two halves of a cons cell,
This could be true for any chosen terminology here. Unless you meant Lisp in general and not this particular dialect, in which case there are counterexamples to that (namely: Clojure, last I checked).
