The term 'Luggage Add-On' can be summarized as an item that is attached to a piece of luggage to increase its capacity or provide additional features. The crossword solution for this term is TAG, which stands for Travel Accessories Group. This is an organization that provides a variety of products designed to enhance the travel experience, such as luggage tags, straps, and locks. These items are designed to make it easier to identify and secure luggage while traveling.