Four dimensional space refers to a mathematical concept that describes an object or system that has four dimensions. Other words that can be used to refer to this concept include four dimensional geometry, four dimensional continuum, and four dimensional universe. In physics, this concept is often associated with theories such as string theory and general relativity, which suggest the existence of additional dimensions beyond the three-dimensional space we can observe. While the concept of four dimensional space may be difficult to visualize, it has important implications for our understanding of the nature of reality and the universe.