Metaverse
A metaverse is a collective virtual shared space, created by the convergence of virtually enhanced physical reality and physically persistent virtual space. It's an interconnected network of 3D virtual worlds where users can interact with each other and digital entities in real-time, often using avatars. 
These environments can mimic or extend beyond the real world, offering experiences like gaming, attending virtual concerts, or working in virtual offices. The concept of the metaverse emphasizes persistence, where these digital spaces continue to exist and evolve even when users are not logged in. 
It's envisioned as a future iteration of the internet, where instead of just browsing, users live, work, and play in a deeply immersive digital universe.