Four-dimensional spaces are a mathematical concept that is often used in the field of physics and engineering. A synonym for four-dimensional spaces is four-dimensional geometry or simply 4D. Other synonymous terms for four-dimensional spaces include spacetime, hyperspace, and fourth dimension. The idea of four-dimensional spaces can be challenging to conceptualize as we live in a three-dimensional world. However, it is a crucial concept in understanding how objects move in space and time. Understanding the various synonyms for four-dimensional spaces is essential in helping to explain this abstract concept in different contexts.