noun
different dimension; another dimension
Refers to a dimension or realm fundamentally different from the ordinary one, often used in science fiction, fantasy, or metaphorically for something extraordinary.
その映画では、主人公が異次元の世界に迷い込む。
In that movie, the protagonist wanders into a different dimension.
彼の発想はいつも異次元だ。
His ideas are always on another level.