A ring is a round band, usually made of metal, worn as ornamental jewelry. The term "ring" by itself always denotes jewellery worn on the finger; when worn as an ornament elsewhere, the body part is specified within the term, e.g., earrings, neck rings, arm rings, and toe rings. Rings always fit snugly around or in the part of the body they ornament, so bands worn loosely, like a bracelet, are not rings. Rings may be made of almost any hard material: wood, bone, stone, metal, glass, gemstone or plastic. They may be set with gemstones (diamond, ruby, sapphire or emerald) or with other types of stone or glass.

Although some people wear rings as mere ornaments or as conspicuous displays of wealth, rings have symbolic functions respecting marriage, exceptional achievement, high status or authority, membership in an organization, and the like. Rings can be made to sport insignia which may be impressed on a wax seal or outfitted with a small compartment in which to conceal things.