A strapless garment consisting of a continuous band of fabric across the torso. Length ranges from covering the entire torso to just covering the breasts, or part of them; the latter two cases can additionally qualify as a bandeau. Traditionally, the only support they provided was due to the stretchiness of the fabric.
In some special cases (ie. a bra is worn underneath a tubetop), this tag can still apply. For example, in post #3622090 and post #3589784, the tubetop tag is still applicable as it is referring to the white garment (which is strapless on its own) and not the bikini top that is worn underneath. Alabama's outfit is a notable example of this.