Uncaught Reference Error

Version 2.5.3
The following code is generating a “Uncaught ReferenceError: jQuery is not defined
at (index):1062”

<script type="text/javascript">
                            jQuery(document).ready(function(){
                                jQuery("div#js-ticket_screentag").css("right","-"+(jQuery("div#js-ticket_screentag span.text").width() + 25)+"px");
                                jQuery("div#js-ticket_screentag").css("opacity",1);
                                jQuery("div#js-ticket_screentag").hover(
                                    function(){
                                        jQuery(this).animate({right: "+="+(jQuery("div#js-ticket_screentag span.text").width() + 25)}, 1000);
                                    },
                                    function(){
                                        jQuery(this).animate({right: "-="+(jQuery("div#js-ticket_screentag span.text").width() + 25)}, 1000);
                                    }
                                );
                            });
                        </script>

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