I think you are looking for Lebesque measure, wikipage.
Quote: "For lower dimensions n = 1, 2, or 3, it coincides with the standard measure of length, area, or volume. In general, it is also called n-dimensional volume, n-volume, hypervolume, or simply volume."
Jo, men chefen Zak Brown er amerikaner. Deres møde med Trump var ikke så heldigt, må jeg sige.