 <p>The function that upcases the previous word is</p> <pre><code>(defun upcase-previous-word () (interactive) (upcase-word -1)) </code></pre> <p>If you want more information on function <code>upcase-word</code>, try <code>M-x describe-function</code> then <code>upcase-word</code>. This assigns <code>M-u</code> to it</p> <pre><code>(global-set-key (kbd "M-u") 'upcase-previous-word) </code></pre>