NoName3 said: "The idea of "universes" in contemporary conception goes back to the US TV show St. Elsewhere as far as I know (open to correction, but make sure you're talking about contemporary conception)."
I'm not sure what you might mean by "contemporary conception", but I believe the term universe is more akin to its meaning/use in Mathematics (a collection that contains all the entities one wishes to consider in a given situation). In movies, TV, or theater, a universe would consist of characters, settings, etc. created by a single author/writer/publisher. The limits regarding where a collection begins/ends are defined by who its creator is.
For example, in the Stephen King universe, one very recognizable element he repeatedly utilizes from his "collection" is the setting (Castle Rock, Maine). Another example is Shonda Rhimes. She has quite a collection of fictional characters in her universe. It is her universe because she is their creator.
In both examples, each of the creators' novels or TV series stand on their own, as individual, unrelated works. They can, however, contain "overlaps" where elements from the creators' universes blend. For example, in King's novels, I believe (not 100 percent sure?) there is a character of a sheriff who is utilized in more than one novel, and in Rhimes' case (as well as with other TV shows not created by Rhimes), there are "crossover" episodes, where characters from one show appear as guest stars in another.
NoName3 also said: "In the final episode of St. Elsewhere, Tommy Westphall, the autistic son of one of the main characters is seen staring into a snow globe that depicts the eponymous hospital. From that final scene, multiple critics and commenters realized that *numerous* shows were related to the St. Elsewhere universe."
Well.. not exactly, but you're correct. It isn't the St. Elsewhere universe, however, but rather the Tommy Westphall universe. Tommy was the creator. Wikipedia explains it more plainly:
"As characters from St. Elsewhere have appeared on other television shows and those shows' characters appeared on more shows, and so on, a "Tommy Westphall Universe" hypothesis was postulated by Dwayne McDuffie where a significant amount of fictional episodic television exists within Tommy Westphall's imagined fictional universe."
The reason I believe that Loopin'theloop has given the best example of what Jorge asked about in his original post is that Me and My Girl (a stand-alone work, from the universe of a completely different creator, with no direct relation to My Fair Lady) very subtly and cleverly brought in a character from the Lerner/Loewe universe (Henry Higgins).
Updated On: 1/11/18 at 09:13 AM