Three-dimensional space

geometric model in which a point is specified by three parameters

Three-dimensional space is a geometric three-parameter model of the physical universe (without considering time) in which all known matter exists. These three dimensions can be labeled by a combination of three chosen from the terms length, width, height, depth, and breadth. Any three directions can be chosen, provided that they do not all lie in the same plane.


  • Motion in three dimensions is not easy to understand. For example, you are probably good at driving a car along a freeway (one-dimensional motion) but would probably have a difficult time in landing an airplane on a runway (three dimensional motion) without a lot of training.
    • Jearl Walker, David Halliday, and Robert Resnick, Fundamentals of Physics (10th ed., 2014), Ch. 4. Motion in Two and Three Dimensions

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