Definition: In the language we like to think of as "fashion-speak", a "shress" is simply a sheer dress. Sheer dress = "shress". See what they did there?
(See also: "Shants")
The "shress" first came to the notice of the Fashion Police in the 2007/2008 season, when various designers (Dior, Christopher Kane, etc) began parading them down their runways. Clearly these designers were (mostly) just having a laugh, but some retailers decided to take the so-called "trend" seriously, and tried to flog the "shresses" to unsuspecting buyers, thus creating an "Emperor's New Clothes" type scenario in which people would be expected to pay a small fortune for... well, nothing really.
And still it goes on. The Fashion Police have yet to hear of anyone other than Agyness Deyn (who doesn't really count) actually wearing a "shress" in real life, but some retailers continue to offer them for sale. The one on this page is a particularly good example of the breed, allowing its wearer to essentially walk around naked, having paid £180 for the privilege. We wouldn't really class it as "not safe for work" because we think the model's wearing a flesh-coloured thong, but we're putting it behind a cut, just to be on the safe side.
It's £180 from Yoox.