What the heck is Steampunk?
By definition, Steampunk refers to a subgenre of science fiction and sometimes fantasy—also in recent years a fashion and lifestyle movement—that incorporates technology and aesthetic designs inspired by 19th-century industrial steam-powered machinery. It emphasizes anachronistic technology, usually from the Victorian era, and takes place in an alternate history setting.
Think airships, mechanical men, and mad scientists with goggles working on time travel. Steampunk is defined by the written works of H.G. Wells (The Time Machine) and Jules Verne (20.000 Leagues Under the Sea) and in movies like Wild West.
The best place I've found to see what Steampunk is all about, whether it's art, fashion or architecture, is on Steampunk Tendencies. You can find them on Facebook, Instagram and Tumblr.