They are unit intervals.
it is how many spaces the number is away from 0 on the numberline. always positive.
To graph a negitive . You would go three spaces back from zero.
Intercostal spaces
pore spaces
The spaces between rocks and soil are called pore spaces or interstitial spaces. These spaces are important for water infiltration, aeration, and root penetration in the soil.
the spaces between the teeth of a comb are called umpernaters :) that's their scientific name.
cementation
The spaces between the topographic lines are called contour intervals. They represent the difference in elevation between each line on a topographic map.
The tufted vertical ridges are called wales. The apparent "spaces" between the wales are actually the base fabric called the ground (which can be plain or twill).
What is outside the cell
nucleoplasm.
If the spaces have been inserted between the letters it is called kerning. If the spaces are put between paragraphs or other elements it is simply called formatting (layout).