Numerology

Numerology is the study of numerical values in the letters of words, names and ideas, and the belief in mystical relationships between numbers and coinciding events.

In Toaru Majutsu no Index, certain numerological aspects are connected to various forms of Magic.

Principles
Two numerological methods are and.

British Royal Family Arc
When Elizard explains to Kamijou Touma about the Curtana, it is mentioned that made use of the four nations of England, Scotland, Wales and Ireland as part of one large nation in the spell he was constructing, in order to use the 'land' aspect symbolized by the number four.

Aleister Crowley Arc
During the events in Windowless Building on December 11th, it was mentioned that the number associated with both Aiwass and Thelema is 93.

Processor Suit Arc
During the events in the evening of December 11th and the morning of December 12th, Aiwass's numerical value of 93 is mentioned again, together with Coronzon's numerical value of 333.

Coronzon Arc
The final barrier of the England-Londinium Fortress was said to have been intentionally randomized, such that enemies cannot make fixed correspondence tables using and other similar methods to untangle it.