The concept of multiple universes has been debated by thinkers in many fields, including physics, cosmology, religion, and literature, since ancient times.
Multiverse refers to extending the concept that we live in a web of interconnected, parallel, physical realities to describe how multiple digital worlds may be woven together or operated in tandem.
Source: George Lawton, Metaverse vs. multiverse vs. omniverse: Key differences, TechTarget, 2022