In general, the term "alien" is used to refer to beings from other planets or celestial bodies within our own universe. When discussing beings from different universes, there isn't a widely established term specifically designated for them.
However, depending on the context, some people might use terms like "interdimensional beings" or "multiversal beings" to describe entities that originate from alternate universes. These terms are often used in science fiction or speculative discussions that involve the concept of multiple universes or dimensions.
Since the idea of beings from other universes is largely speculative and falls outside our current scientific understanding, there isn't a universally recognized or standardized term for such entities. It's important to note that discussions involving other universes or interdimensional beings often delve into theoretical or fictional concepts, and they may vary depending on the context or the specific fiction or theory being explored.