Magic

Magic (魔法, Mahō) is the main form of combat for Mages, and is bought and sold all throughout the world.
  
History
Magic has been around for centuries. All Magics have come from The One Magic, the original source of all types of Magic. It was once oppressed and feared, but gradually became an everyday phenomenon.

Overview
Magic is the physical embodiment of the spirit. When the physical spirit of an organism connects with the spiritual flow of nature, the spirit forms Magic as a product of the connection. Only ten percent of the world's population is able to use Magic, which is noted to keep a balance between ordinary people and those with Magic. It takes an enormous amount of concentration and mental ability to use Magic. Mages can learn multiple styles of Magic, but it is noteworthy that many Mages have natural affinities for their own Magic style, such as Erza Scarlet instinctively using a rudimentary form of Requip Magic as a child. 

Usage
All kinds of Magic are used in Earth Land and formerly in Edolas, and they can be used for many purposes such as offense, defense, supporting, and healing. Magic is used by exerting their Magic Power as a wide variety of spells or by focusing it into an external source. However some items and weapons such as Edolas Items use Lacrima to power them. In order to learn Magic you must train your intellect and spirit.

Magic Power
To utilize Magic, a Mage must use Magic Power. Magic Power is the source of Power for all Mages, it is composed of Eternano. Every Mage has a container inside their body that determines the limits of their Magic Power. In the case that it becomes empty, Eternano comes from the atmosphere and enters the Mages' body and after a while, their Magic Power is returned to normal. However, recent studies has identified another part of the Mages' Magic container that isn't used normally and contains their dormant power called Second Origin. If the Power within this second container is reached, then the Mage in question, will receive an enormous boost in Magic Power.

Taboo
Every Magic has its own set of rules that must never be broken, that is a taboo. Different taboos that are broken have different effects on the user's body, but in the end, the fate of everyone who breaks a taboo is to disappear.

Classifications
There are two main classifications of Magic: Caster Magic and Holder Magic. Within these two there are many sub categories such as Edolas Items, Lost Magic, and Magic Items. 

• Caster Magic: (キャスターマジック Kyasutā Majikku) is Magic that is expelled from the body as opposed to Magic done through the use of a weapon or outside source.

• Holder Magic: (ホルダーのマジック Horudā Majikku) is Magic that requires a Mage to use an external source to produce the Magic. It usually requires the use of Magic Power, though there are some exceptions such as Edolas Items that are powered by Lacrima.

• Lost Magic: (失われた魔法 Rosuto Majikku) is a type of Magic that has been obliterated from the history of the world due to their immense power and the sheer gravity of their side effects. However, users of such Magic still exist, though the Magic itself is believed to be extremely rare. 

(c) http://fairytail.wikia.com/wiki/Lost_Magic