I came across this curious term in an article about 19th century or related ‘industrial’ style fonts.

As I have barely read science fiction, I had to look it up, and found it a wonderful way to describe a genre centred on steam-powered and other 19th century technology.  The Oxford English Dictionary describes it as:

‘A writer of science fiction which has a historical setting (especially based on industrialized, nineteenth-century society) and characteristically features steam-powered, mechanized machinery rather than electronic technology; (also) such writing as a subgenre of science fiction.’