 While the name " bikini " was at first applied only to beachwear that revealed the wearer 's navel , today the fashion industry considers any two @-@ piece swimsuit a bikini . Modern bikini fashions are characterized by a simple , brief design : two triangles of fabric that form a bra and cover the woman 's breasts and a third that forms a panty cut below the navel that covers the groin and the buttocks . 
