Literary steam punk is a strange and mysterious genre or sub-classifications within a larger genre. For example, a science fiction or fantasy story, were it to have an airship or automaton would have elements of steam punk, or a steam punk story, were it to have fairies or aliens, would be considered to have elements of fantasy or science fiction. The word “punk” is used as a method of “stealing” ideas or inventions from another time/reality/ or world. The term steam punk seems to envelope a large mass of ideas that need sorting out. The history of steam punk is well defined in Wikipedia and other sources, but an analysis of this genre is controversial, so here is a rational layout, using definitive terms:
Victorian: Lucky for us Queen Victoria ruled Britain for many years during a time in the world of high stakes and adventure. Many Steam punk stories are set in this era also because it was the age of science where new inventions were conjured constantly. They can include glamorous fashions from the time period while ignoring cultural convention or proper etiquette. In short, an author has many options with setting, and Victorian works well. Most settings help define genre such as American Wild West, Gothic , Industrial Revolution etc.
Alternate history, retro futurism, retrotronics: Taking a moment in time and blending new elements to rewrite history. i.e. giving Napoleon ray guns or making Abe Lincoln a vampire slayer. Jules Vern and Edgar Alan Poe were originators of this genre.
Speculative fiction: usually refers to future events that could possible happen. They can be post apocalyptic and dystopian. What if Britain won the American Revolution? What if there was a nuclear holocaust? What if?
Cyberpunk: Infusing cyber technology into a historical setting such as computers, electricity, robots, aliens, or laser weaponry. Think Cowboys and Aliens. I will include time machines in this category because whatever the source of power, steam/clockwork/gas/electrical, the warping of time creates an element beyond any technology we could imagine.
Gas Lamp, Urban myth: Includes paranormal events that take place in a historical setting such as Bramstoker’s Dracula. They include elements of magic, mad science, optical illusions and creatures beyond normal rules of existence. These legends are well known for eliciting fear in the hearts of readers and therefore get re-approached many times.
Clockwork: Often synonymous with steam punk, this includes clockwork inventions that go beyond the confines of reality i.e. the automaton and other devices based on simple and complex mechanics like booby traps, weapons, locks, vehicles and so on.
Kite work/ Air work/ Water work etc.: Inventions using the power of wind water and air with the ability to supersede average travel before it’s time i.e. gliders, ballooning, dirigibles, air ships, blimps, hydrogen or gas powered flight, steam ships and submersibles.
So the next time you are asked to classify the Invention of Hugo Cabaret do not merely say, steam punk. Saying a speculative, clockwork fiction set in historical France would give a more accurate description.