title: LISP terminology
body: <p>What does the letter 't' mean in LISP?</p>
  
  <p>ex:</p>
  
  <pre><code>(defun last2 (lst)
     (cond ((null lst) nil)
         ((null (cdr lst)) (car lst))
          (t (last2 (cdr lst)))))
  </code></pre>
  
  <p>My textbook is a coursepack so it doesn't quite explain all the meanings.
  Thanks.</p>