CONS function make new cons object. The cons cell contains exactly two values. The first is named car, the second is named cdr. These cells are used to create one-way linked lists. See also CAR, CDR and LIST.

These names come from historical names "Contents of Address part of Register" and "Contents of Decrement part of Register".

(cons 1 2) => (1 . 2)
(cons 1 (cons 2 (cons 3 nil))) => (1 2 3)
(cons 1 (cons 2 (cons 3 'x))) => (1 2 3 . X)
(cons (cons (cons 'a 'b) 'c) 'd) => (((A . B) . C) . D)
(car (cons 1 2)) => 1
(cdr (cons 1 2)) => 2