ANSI Common Lisp 14 Conses 14.1 Cons Concepts
14.1.2 Conses as Lists
A list is a chain of conses in which the car of each
cons is an element of the list,
and the cdr of each cons is either the next
link in the chain or a terminating atom.
A proper list is a list terminated by the empty list.
The empty list is a proper list, but is not a cons.
An improper list is a list that is not a proper list;
that is, it is a circular list or a dotted list.
A dotted list is a list that has a terminating atom
that is not the empty list. A non-nil atom by itself
is not considered to be a list of any kind - not even a dotted list.
A circular list is a chain of conses that has no termination
because some cons in the chain is the cdr of a later cons.
Some defined names relating to lists.
220.127.116.11 Lists as Association Lists
18.104.22.168 Lists as Sets
22.214.171.124 General Restrictions on Parameters that must be Lists