1) Accessory worn near the navel 2) It may be big on a cowboy 3) Pants-accessory clasp 
(from the article `jewelry`) Another fine example that typifies the plastic decorative repertory of the flamboyant Gothic style is a silver belt buckle from Sweden (Historical ... clasp or catch, particularly for fastening the ends of a belt; or a clasplike ornament, especially for shoes. The belt buckle was often used in ... [2 rel...
[n] - the buckle used to fasten a belt
noun the buckle used to fasten a belt