In Euclidean geometry, the fourth dimension refers to a space with four dimensions, in contrast to a two-dimensional xy-plane and a three-dimensional xyz-plane. While two-dimensional spaces contain two vectors and three-dimensional space contains three vectors, every point in a space in the fourth dimension has four vectors.
A cube that exists in four dimensions of Euclidean geometry is known as a hypercube. Using mathematical notation, a point in the fourth dimension is often represented as a vector of (w, x, y, z). In physics, the term fourth dimension refers to spacetime, in which the fourth dimension, time, exists alongside the three dimensions of conventional space. This type of fourth dimension is known as Minkowski space and is used in special relativity.