Here's a thought.

 How are parallel universes categorized? I mean in Multi-World Theory if you take that to mean that multiple universes that split from each other are actually a fundamental of existence. They don't think that, for the most part, but a lot of pop science books have been written about it. I personally, lack the Latin to make this decision.

 Not like in comic books, which seems to be relatively scattershot. DC and Marvel both have multiverses, neither company has had a consistent policy. I want to say Marvel would name realities based on when the comic was released. I'm not going to look it up, but it's like the Ultimate universe is Earth-2001. Mainstream Marvel is Earth-616 and was supposed to show how relatively unimportant it is. It is, but you know what I mean.

 DC seems to like having a noted Main Earth. Earth-One, New Earth, etc. It's had a couple of universal reboots - i.e., a chance to rewrite the entire line, a la fan fiction - in the last 10 years, so I don't know how they're doing it now. Again, I'm not looking it up.

 They're universes are decided by editorial fiat and regular cosmic occurrences, or if you like, crises. Marvel, on the other hand, says universal split occurs at certain points that make for good storytelling and/or covering up something that's just embarrassing. They had a DC-style reboot a couple years ago, but I think the only thing that actually change was to bring certain popular characters into the Mainstream line. Again, fan faction.

 Anyway. Who knows how they do it now? It's interesting that Human Marvel - like the people who spend time with the MCU or the Spider-Verse - is introducing their whole multiple universe thing at all, much less this relatively quickly. The Squadron Supreme was nearly 10 years into the line and Marvel's always had that connected universe.

 DC really didn't do it all that much until the '60s, basically following Marvel's lead. Batman in the Jusrice League could be doing something entirely different in his own books, his World's Finest team-up with Superman book, and just wherever he wound up that month. Same with everyone, really. It's why Superman and Batman teamed up with Jonah Hex and the Haunted Tank so often and Wonder Woman teamed with Beowulf.

 The problem with their mashing into one coherent world came when the Barry Allen Flash meet the Jay Garrick Flash, even though only a couple of years separated them. Like '47 to '52, admittedly a lifetime in comics. It was a pain because just about every character was owned by the same people but not the same company, if that makes sense. Flash Comics and All-Star Comics and National Comics and Action Comics and Detective Comics were all their own little worlds. Wildcat, Ted Grant, was inspired to become a mystery man after reading a Green Lanter, Allan Scott, comics.

 Marvel was even less organized than that. Some titles only lasted one issue and the next issue would have a completely different name. Indeed, their Marvel Comics was renamed Marvel Mystery Comics after one issue and introducing most of the characters Marvel uses as their "Golden Age," like the Sub-Mariner and the original Human Torch. It later became Mystery Comics and finally Marvel Tales, which became a horror anthology. It later was a reprint mag, mostly for Spider-Man.

 But I ramble. So DC squeezed all these books together and spent the second half of the century acquiring the rights to every other long-underwear character that Marvel didn't own. Like Plastic Man and the Spirit came from Quality Comics and the characters Allen Moore based his Watchmen characters own (Blue Beetle, the Question, etc.) came from Charlton Comics. After suing Whiz Comics for bullshit reasons and won, so they got Captain Marvel, who I refuse to call Shazam.

 They all came from different universes or went to different universes. The Quality characters, for example, went to a universe where the Second World War was still going on. The others were squeezed in with the Crisis On Infinite Earths which also got rid of their multiverse for a couple of decades. In theory, anyway. They keep making such a dog's biscuit out of it, they have to keep turning the universe off and turning it on again. Undoubtly, the success or lack thereof from the DCCU will have some impact if it hasn't already.

 But none of those count in this thought experiment. Would categorization determine number? Like, maybe the South won the Civil War and ceased to be quite as awful or won the Civil War and became that world's Nazis. Both from Harry Turtledove, too. Suppose those worlds exist somewhere in the cosmic static. If you could travel through them, how would you chart them?