Prefix&#x2F;postfix&#x2F;infix refer to the order in which you write operations and their operands—equivalently you can think of preorder&#x2F;postorder&#x2F;inorder traversals of the syntax tree.<p><pre><code>    AST          +
                &#x2F; \
               *   5
              &#x2F; \
             2   3

    Infix    2 * 3 + 5
             2 times 3 plus 5.

    Prefix   + * 2 3 5
    Lisp     (+ (* 2 3) 5)
             The sum of the product of 2 and 3, and 5.

    Postfix  2 3 * 5 +
             With 2 and 3, multiply. Then with 5, add.</code></pre>