Grant Morrison: Sigil Magick

A sigil (from Latin sigillum "seal") is a symbol used in magic. The term has usually referred to in the context of chaos magic, a symbolic representation of the magician's desired outcome.

In modern uses, the concept was mostly popularized by Austin Osman Spare, who published a method by which the words of a statement of intent are reduced into an abstract design; the sigil is then charged with the will of the creator. Spare's technique, now known as sigilization, has become a core element of chaos magic.

The inherently individualistic nature of chaos magic leads most chaos magicians to prepare and cast (or "charge") sigils in unique ways, as the process of sigilization has not been rigorously defined. Sigils are used for spells as well as for the creation of thoughtforms.

Unlike with traditional sigils, whose creators made use of traditional lore passed down from generations or from books, modern users often create sigils entirely themselves and devise individual means of "charging" them with metaphysical power.

A "hypersigil" is an extended work of art with magical meaning and willpower, created using adapted processes of sigilization.
The term was popularized (if not coined) by Grant Morrison. His comic book series The Invisibles was intended as a hypersigil.
Along with being used in chaos magic, the practice of using a "Sigil" in magical arts is commonly used amongst Occultist and New Age Mystics. The purpose of the use of a sigil in these varying groups can be classified under the Conjuration aspect of the Arcane or Magical Arts.