lispdoc - results for nth 

(nth n list)
Function: Return the nth object in a list where the car is the zero-th element.
Example:
(defun slot-definition-type (slot) (nth 7 slot))
Mentioned in:
CLtL2 - 15.2. Lists
HyperSpec - Accessor NTH
On Lisp - An ATN Compiler
On Lisp - Conditional Evaluation
On Lisp - Functional Design
On Lisp - Local Functions
On Lisp - New Utilities (Computation at Compile-Time)
On Lisp - When Capture Occurs
PCL - list manipulation functions
PCL - other structures
Successful Lisp - closures
(nth-value n form)
Function: Evaluate FORM and return the Nth value (zero based). This involves no consing when N is a trivial constant integer.
Example:
(defun ajax-function-name (fn)
  (or (sb-kernel:%fun-name fn)
      (string
       (nth-value 2
                  (function-lambda-expression
                   fn)))))
Mentioned in:
CLtL2 - 7.10.1. Constructs for Handling Multiple Values
HyperSpec - Macro NTH-VALUE
(alexandria.0.dev:nth-value-or nth-value &body forms)
Function: Evaluates FORM arguments one at a time, until the NTH-VALUE returned by one of the forms is true. It then returns all the values returned by evaluating that form. If none of the forms return a true nth value, this form returns NIL.
  

By Bill Moorier