Simplified Common Lisp reference
Symbol class: Conses, Lists and related functions
Symbol type: function
cddrlist => value
Argument description:
list cons or full list

CDDR function is composition of two CDR functions. That is, (CDDR X) is same as (CDR (CDR X)). There are other CAR and CDR combinations, see HyperSpec, CAR and CDR.

(cddr '(1 2 3 4)) => (3 4)
(cddr '(1 2 . x)) => X
(cddr '(1 . nil)) => NIL
(cddr nil) => NIL
Function indexFull documentation for cddr (HyperSpec)