11th dimension may refer to:
- Supergravity, a field theory that combines the principles of supersymmetry and general relativity.
- 11-dimensional spacetime, which appears in M-theory, a proposed "master theory" that unifies the five superstring theories
- "11th Dimension" (song), by Julian Casablancas, 2009
The 11th dimension is a characteristic of spacetime that has been proposed as a possible answer to questions that arise in Superstring Theory, which involves the existence of 9 dimensions of space and 1 dimension of time.[clarification needed] Humans can understand only 3 spatial dimensions and one time dimension, and the remaining 6 spatial dimensions are compactified. Some physicists[who?] have suggested that there exist 11 dimensions, which are compactified like the six dimensions. Michio Kaku, an American theoretical physicist, has said he believes the multiverse of universe is 11-dimensional. In string theory, the multiverse is made of different dimensions but the highest is 11th dimension. Beyond 11 dimensions, the universe would become unstable and dimensions higher than 11 would collapse to an 11-dimensional universe.