- For other uses of the word plane, see plane.
In cosmology and metaphysics, a plane or dimension is a generalized region of space. Commonly, plane refers to a theoretical region beyond the known universe, or the region containing the universe itself. This term is used by association with the mathematical concept of dimensions, though it is a misnomer: mathematical planes are two-dimensional, while the cosmological plane containing Earth has at least four dimensions. This does not necessarily mean there may not be planes of existence having exactly two (or fewer) dimensions, but someone who refers to a plane in the cosmological sense should not be interpreted literally.
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