lispdoc - results for defparameter

(defparameter var val &optional (doc nil docp))
Function: Define a parameter that is not normally changed by the program, but that may be changed without causing an error. Declare the variable special and sets its value to VAL, overwriting any previous value. The third argument is an optional documentation string for the parameter.
 Mentioned in:
CLtL2 - 25.1.3. Compilation Environment
CLtL2 - 5.3.2. Declaring Global Variables and Named Constants
CLtL2 - 9.1. Declaration Syntax
CLtL2 - 9.2. Declaration Specifiers
On Lisp - Common Lisp Implementation
PCL - constants
PCL - dynamic aka special variables
PCL - macros standard control constructs
PCL - the heart of a spam filter
PCL - the mighty loop
PCL - the pretty printer backend
Successful Lisp - chapter10
Successful Lisp - chapter28
Successful Lisp - global vars and consts
Successful Lisp - special