This section deals with variations in the top half or the bikini, in other words, the species of the soutien-gorge. This French term (plural soutiens-gorge) is literally translated as a bosom support. In Bikini Science it is a generic term for a bare-midriff bikini top regardless of its species, although it is also expanded to include an underwear top as well as casual clothes.
In a gross sense all soutien-gorge are divided into four types: the brassière, halter, bandeau, and vest. These are differentiated by the number of straps, and thus, in a topological sense, by the number of edges to the garment. (A bandeau for example has no straps and two edges). A more detail discussion of these facets is found in the pages that deal with the specific species. (Note that to some extent these variations in straps also apply to the maillot.)
Despite the fact that four types of can define the world of soutien-gorge quite a few species are defined in this section because it advances our study to define a number of species in terms of a fashion silhouette. For example the underwire bra and the sports bra are both types of brassière, but they have radically different methods of support, exposure, and intent.
The variations herein also include species found in casual wear. These include croptops, vests, and others because they complete the set of species and because they are sometimes the top half of a bikini. Likewise, the absence of a top, or topless, is also included.
The species of soutien-gorge presented here also relate to many other issues, including changing actions, fasteners and strapwork, exposures, and the exposure codes.