I finally figured out how to correct the problem – I was using the “My Page Order” Plug In and had to edit my-page-order/mypageorder.php by removing the word “Pages” from the line:
$title = apply_filters(‘widget_title’, empty( $instance[‘title’] ) ? __( ‘Pages’ ) : $instance[‘title’]);
It now appears as:
$title = apply_filters(‘widget_title’, empty( $instance[‘title’] ) ? __( ” ) : $instance[‘title’]);
and the word “Pages” has disappeared from the top of the sidebar list.