Why would wear low-cut dress in the beach though. Well I just tagged it as bikini because of my perception of the image that's all.
@Qpax Which is absolutely correct imo. If something might not be efined completely, then one should look at the context of an image or a character. And here, a bikini top mkes probably the most sense, even if it could also be a dress. But a dress is less likely (Occam's Razor :3).