The Prime is the center point of the Istarian universe and the convergence point for all energies of the Realms.
The Planar Plateau is a 2-dimensional plane on which all of the Realms orbit the Prime.
The Prime Ring is another name for the Inner Realms, those Realms that touch the Prime directly.
The Inner Realms are Realms that most closely orbit the Prime, often touching it directly. Traditional they are the oldest and most stable of the Realms.
The Inner Realms consist of the Realms of Fire, Water, Air, Earth, Life, Spirit, Blight and Energy.
The Outer Realms are realms that reside far from the Prime and often have irregular or inconsistent orbits making them difficult to see or reach at times.
The Outer Realms consist of the Realms of Nature, Storm, Bounty, Expanse, Order, Chaos, Light, Shadow, Dawn and Twilight.
The Realm of Void is not actually a Realm, but rather the space between the Realms. It is the emptiness in which the Prime and other Realms exist.
The Realm of Life is one of the Inner Realms and one of the most closely tied to the Prime. During the Age of the Sorcerer two great focal points were constructed; the Cleric's Tower and the Tower of Healing.