A ring of wood, metal or plastic. (Cambridge Dictionary)
A ring-shaped earning (=a piece of jewellery that hangs from the ear) (Cambridge Dictionary)
A circular band of metal, wood, or similar material, especially one used for binding the staves of barrels or forming part of a framework. (Oxford Dictionaries)
A hoop is a large ring made of wood, metal, or plastic. (Collins Dictionary)
A circular strip used especially for holding together the staves of containers or as a plaything. (Merriam – Webster)
Lumina LED Hula Hoop.