Returns a list containing all but the first element of the specified list
(cdr list)
A list containing all the elements of list, except the first element (but see Note below). If the list is empty, cdr returns nil.
Command: (cdr '(a b c))
(B C)
Command: (cdr '((a b) c))
(C)
Command: (cdr '())
nil
Command: (cdr '(a . b))
B
Command: (cdr '(1 . "Text"))
"Text"
The Point Lists topic in the AutoLISP Developer's Guide.