A bikini is a two-piece swimsuit primarily worn by women that features two triangles of fabric on top that cover the breasts, and two triangles of fabric on the bottom: the front covering the pelvis but exposing the navel, and the back covering the buttocks. The size of the top and bottom can vary, from bikinis that offer full coverage of the breasts, pelvis, and buttocks, to more revealing designs with a thong or G-string bottom that covers only the mons pubis, but exposes the buttocks, and a top that covers only the areolae.