Accessory (noun)

A thing that can be added to something else in order to make it more useful, versatile, or attractive.

Origin:

Late middle english: from old french acessoire, from late latin accessoryum, from accedere "go with".

Examples:

1. She added a matching accessory to her outfit.
2. The camera comes with several accessories, including a lens and a case.
3. The car had several accessories, such as a sunroof and a navigation system.
4. The accessory made the dress look more stylish.
5. The accessory made the gadget more functional.