Well, cdr can't really be spoken aloud unless you make up a way to pronounce it (which of course people do). And you could do the same for hp, rp, and the rest... adding an "o" sound gives some nice words, like hop, top, and fop. Kind of a Dr. Suess feel. :)
So if you have
(def foo (a b . c) ...stuff...)
and you call (foo 1 2 3 4 5), a is bound to 1, b is bound to 2, and c is bound to the list (3 4 5).
And
(def foo a ...stuff...)
is just shorthand for
(def foo ( . a) ...stuff...).
So calling (foo 1 2 3) in this case means a is bound to the list (1 2 3).
