Lexology

Lexology is the art of magic done via runes.
Runes are used to specify important aspects of the spell and to allow the magician to constrain the side-effects that the spell may take.
Because magic requires the belief of the spellcaster and isn't a product of the runes themselves, copying lexographic runes will not cast the spell. Rather, the spellcaster must have a knowledge of the meaning of the runes so they can be used to assist in remembering and building the underlying belief required for the spell's effect to occur.
In fact, the runes themselves aren't important, and can be used interchangeably. They are just a method to allow the spellcaster to remember what effect they're wanting, how the effect can occur, and what potential side-effects the desired effect can have.

Side-Effects

Lexology doesn't specify any side-effects of the magical spell being cast.  If it did, they wouldn't be side-effects, and would instead be part of the spell. Rather, it is used to specify the potential class the side effects could take.
It's unclear if side-effects are a necessary outcome of spells, but it is widely believed to do so.  By believing they will occur within a specifically constrained class, lexology allows boundaries for those side-effects.   
It is still necessary for the magician to believe that these effects are proper and sufficient for the spell they're casting.  If they don't, their spell will continue to have effects as defined, but also have unexpected outcomes.

Example

If a magician wanted to cast a Levitation spell, they may recognize this can be done by changing properties of the object being levitated (making it less dense), by affecting gravity (decreasing the attraction between the earth and the levitated object), magnetism (giving the earth and object the same polairty), or some other mechanism.
Each of these methods of levitation could have its own available classes of side-effects. For example, affecting gravity may cause the flying object to turn upside down or compress. Magnetism may change the material of the flying object or cause other things to be attracted to it.
A levitation rune would then be connected to a density, gravity, or magnetism rune.
The general levitation effect itself may have modifications, independent of the method. It may have an appearance of a cloud or have a traveling velocity, which would need to be connected to the general levitation rune Further specifications or additions to the spell would similarly need to be connected in the proper manner. Only the levitation rune itself is specific to this spell, all other runes are generally useful in a variety of spells.

Magic Research: Lexology

Magic Researchers can specialize in lexology research.

Utility

Lexology is one method of preventing excessive magical side-effects.

Inventor(s)

Ameron Binkley with the assistance of Marten Theus and inspiration from Elina Bucknight.

Access & Availability

While anyone is capable of performing Lexology, most runes are only taught to a few select students, allowing the government and Teles Council to control who can make use of magic.

Discovery

Invented by Ameron Binkley in 459 to build a framework for the prevention of excessive Magical Side-Effects.