Enoch

Enoch (エノク) is a term that is used within the Toaru series to refer to the of magic and beliefs,  based around a supposed angelic.

Etymology
is a name in the Bible used to refer to two characters, first being the son of, and the other, the ancestor of. The system and the language it is based on is named after the latter due to assertions that Enoch was the last human to know the language (before Dee and Kelley).

Enochian Chess
 is a four-player variant developed by founders of the Golden Dawn and incorporated into their magical system. Used for competition and divination, the game has four differently colored sets of pieces corresponding to the four elements, with pieces identified with Egyptian deities (the king for Osiris, the queen for Isis, the knight for Horus, the bishop for Aroueris and the rook for Nephthys). The board is multi-colored, divided into four sub-boards with one of the four elemental colors dominant in each.

Background
The Enochian system of magic is derived from the writings of and  in the late 16th century, based on a supposedly angelic language.

Enochian elements were among the various components which were incorporated into the Golden Dawn's magical system. One of the cabal's founders, Samuel Liddell MacGregor Mathers, played Enochian chess.

Deep Blood Arc
The term Enoch was used by Index during her first meeting with Himegami Aisa regarding her validity as a magician, included in with the likes of Kabbalah, Hermeticism, Vision of Mercury, and Modern Astrology. It can be assumed that Index was referring to Enoch as a school of thought or belief like Kabbalah.

Return to England Arc
Enoch was referred to during the events surrounding the reproduced Golden Dawn, and chess pieces based on Egyptian deities (most likely Enochian chess pieces) were used for magic.