Notarikon

Notarikon (ノタリコン) is a method of deriving a word, akin to the creation of an acronym, by using each of inital or final letters to stand for another word, forming a sentence or idea out of the words.

In Toaru Majutsu no Index, it is referred to as a quick Kabbalah reading method. It is a unique pronunciation method of only using the first alphabet, with the aim of turning it into a code and making it quicker to read.

Etymology
The word "notarikon" is borrowed from Greek language νοταρικόν, which in its turn was derived from the Latin word "notarius," meaning "shorthand writer."

Principles
The technique is used in Toaru Majutsu no Index specifically that of Index's Spell Intercept. Kamachi Kazuma's technique is to have a sentence he had written translated into English first and then using the first letters of each word for the "codes" used for her Spell Intercept. Below is the code used by Index for her Spell Intercept of Sherry Cromwell's golem, as shown in the original Japanese light novel : "M B F P A D C O G"

The accompanying meaning for it in the original Japanese text, as well as the romaji:

"「両足を平行に配置し重心を崩せ」" ("Ryōashi o Heikō ni Haichi Shi Jūshin o Kuzuse")

And the literal meaning of the above sentence:

"Place both legs parallel and destroy the center of gravity."

One can then conjecture the translated meaning of the codes used:

"Move Both Feet Parallel And Destroy Center of Gravity"

Kazakiri Hyouka Arc
The first use of Notarikon seen in the series, was when Index made use of Spell Intercept to interfere with Sherry Cromwell's golem when it attacked her.

Daihasei Festival Arc
Stiyl Magnus used a notation to quickly disperse bystanders with a spell, when he and Kamijou Touma discovered the bloodied body of Himegami Aisa after Oriana Thomson attacked her.

Acqua of the Back Arc
Acqua of the Back made use of a Notarikon incantation for an attack in conjunction with his Divine Mother's Mercy, during his battle with Kanzaki Kaori and the Amakusas.

British Royal Family Arc
Guided by Index, Princess Villian made use of a Notarikon incantation to neutralize the Mokkerkalfe guarding the facility under Buckingham Palace.

Coronzon Arc
The Female Knight made use of a Notarikon incantation during the battle with the reproduced Golden Dawn on the roads between London and Edinburgh.