The "Fourth Dimension" is often referred to as a spatial dimension beyond the three familiar dimensions of length, width, and height. In physics, it is commonly associated with time, forming the concept of spacetime, where time is treated as a dimension similar to the three spatial dimensions. This idea helps explain how objects move and interact in the universe. In mathematics, the fourth dimension can also refer to a hypothetical spatial dimension that is perpendicular to the three spatial dimensions we experience. This concept is explored in various fields, including geometry and theoretical physics, and is often visualized using hypercubes or tesseracts.