multiverse
This term describes a theoretical framework where our universe is just one of many. It carries a strong connotation of infinite possibility and cosmic scale, often appearing in theoretical physics and speculative science fiction to explain quantum branching or the existence of alternate versions of reality. As a noun, it is typically treated as a singular entity encompassing all possible universes. While it can be pluralized in highly theoretical discussions regarding different types of multiverse models, it is most commonly used as a singular collective noun.
Meanings
A hypothetical collection of multiple diverse universes, including the one we inhabit, which may coexist simultaneously.
"The theory of the multiverse suggests that every possible outcome of every event occurs in a different reality."