There are still many terms from classic SF that remain unresearched, and, as new resources are put online, the Historical Dictionary of Science Fiction will be updated. Boing Boing is syndicating new entries from the HDSF on a regular basis.
The best-known non-musical opera is probably the soap opera, a term that arose in the late 1930s referring to melodramatic domestic serial dramas on radio or TV, so called because these programs were sponsored by soap companies. This was preceded by the early-1920s horse opera, for a Western.
The only truly prominent science-fictional opera is the space opera, a sprawling adventure-driven story set in outer space. This term was coined by superfan Wilson "Bob" Tucker in 1941, explicitly acknowledging its horse and soap predecessors. While it was originally pejorative, sneering at the hackneyed and clichéd nature of these stories, it now has a more neutral (or even affectionately positive) connotation when referring to science fiction of the type pioneered in the 1930s pulp magazines by such authors as E. E. "Doc" Smith and Edmond Hamilton.
With the great interest in subgenres among SF fans (or, perhaps more cynically, among people who want to market stories to them), it should be no surprise that a sprawling adventure-driven story based on time travel rather than space travel would get its own name: obviously, time opera. Coined in the 1950s, apparently by Anthony Boucher, the editor of the Magazine of Fantasy & Science Fiction, it avoids the suggestion of unsophistication that space opera has, probably because time operas are simply not common enough to have become annoyingly clichéd. The term itself is likewise less common, but has remained in use for almost seven decades. But while there are occasional nonce uses—Game of Thrones has been referred to as a dragon opera—there sadly don't seem to be many other major opera subgenres to follow.
