Meaning of four-dimensional

four-di•men•sion•al

Pronunciation: (fôr'di-men'shu-nl, fōr'-), [key]
— adj. Math.
  1. of a space having points, or a set having elements, which require four coordinates for their unique determination.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.