di•men•sion dĭmĕn′shən
 n. The fundamental construct of The Universe.

n. A measure of spatial extent, especially width, height, or length.

n. Extent or magnitude; scope.

n. Aspect; element.
Spoiler alert – Only the first definition matters.
Our observable universe is made entirely of Dimension. Everything.
Not atoms, not quarks, not protons, not neutrons, not neutrinos, not leptons, not dark matter, not dark energy, or any other baryonic construct yet postulated.
It is all Dimension, nothing else.
In geeky terms, Dimension is an infinitely variable spherical fractal manifold.
Dimension has a distinctive geometry. The geometry is an ever repeating pattern known as a fractal, and it is incredibly simple.
Dimension is the shape of a horned tori.
The geometry of Dimension appears to the human eye, and therefore, the human mind, as a sphere. This fact is because the dominant, and in fact, the ONLY geometry present in the Universe is the fractal structure of the most basic unit, the unit of Dimension.
Everything you sense is made of fractal spheres. Everything.
There are no straight lines, or circles, or parabolas, or points, or planes or other geometries you have been taught. Those constructs are generated solely within the human mind. They are illusions at best and hindrances to understanding the real structure of the Universe.
You know the spherical fractal pattern of Dimension well, because you see, feel, hear, touch and smell it every day. Sometimes it looks like the arrangement of petals on a flower. Sometimes like a seashell, or a galaxy. You see it in the clouds. You hear it in music. You feel it on your skin. Your nose knows how to decode fractal patterns.
It is all the same fractal, viewed at some scale you senses understand. The reason everything appears as it does is because it is all related by a common geometry, so no matter how closely you look, the pattern repeats over and over and over.
Oh, and the fractal geometry of Dimension is what holds space open.
In a clowncar sort of way, Dimension is a sphere made of grunges of whirlpools that all join at the center of the sphere. All the whirlpools seems to disappear into the middle, somewhere. No matter how you view the sphere, you are looking down a whirlpool toward the center of the sphere.. You are looking at a fractal spiral, and you are looking at what holds all space open.
The shape of the spherical fractal spiral is a seemingly never ending compression that gets teenier and teenier until it literally crosses a boundary and has no dimension at all.
In fact, the very center of the fractal spiral DOES compress to nothingness represented by a mathematical limit. The limit forms a special type of gate which joins Dimensioned and Undimensioned. The mathematical boundary joining Dimensioned to Undimensioned is called a Higgs Gate.
The spherical fractal vortex shape is what produces gravity, and every other force we see and feel every day. It’s because the pointy end of the fractal is connected to a Higgs Gate that is impossibly compressed on one side, and impossibly uncompressed on the other.
Every unit of Dimension is connected to a Higgs Gate, somewhere. Therefore, everywhere there is dimension, there is space, and everywhere there is space, there is fractal compression we understand as gravity.
When you swim in the part of The Pool that describes Higgs Gates, you will see how easy Dimension is to understand.
The Pool is also a spherical fractal vortex. If you swim here regularly, you will begin to understand where you came from, and where you are going. Simple stuff, really.