Simplified Common Lisp reference
Symbol class: Functions, Evaluation, Flow Control, Definitions and Syntax
Symbol type: special form
setqpairs(zero or more) => an object
Argument description:
pairs pairs of variables and values

SETQ special form sets a variable. If a variable name is not know, implementation may create new one global and dynamic one. See also LET, SETF.

(let (a b) (setq a 4) (setq b 3) (setq a (+ a b))) => 7
Function indexFull documentation for setq (HyperSpec)