<?php 
                global $wpdb;
                $tablename = $wpdb->prefix.'terms';
                $query = 'SELECT * FROM '.$tablename;
                $terms = $wpdb->get_results($query);
                echo "<select name='csn_term' id='csn_term' style='height:25px; font-size:16px;'>";
                foreach($terms as $term) {
                    echo "<option value='".$term->term_id."'>".$term->name."</option>";
                }
                echo "</select>"
            ?>