So googles definition:
sig·il
ˈsijəl/
noun
plural noun: sigils
an inscribed or painted symbol considered to have magical
power.
archaic
a seal.
"the supply wains bore the High King's sigil"
literary
a sign or symbol.
From Wikipedia:
A sigil is a symbol used in magic. The term has usually
referred to a type of pictorial signature of a demon or other entity; in modern
usage, especially in the context of chaos magic, it refers to a symbolic
representation of the magician's desired outcome.
In medieval ceremonial magic, the term sigil was commonly
used to refer to occult signs which represented various angels and demons which
the magician might summon. The magical training books called grimoires often
listed pages of such sigils. A particularly well-known list is in The Lesser
Key of Solomon, in which the sigils of the 72 princes of the hierarchy of hell
are given for the magician's use. Such sigils were considered to be the
equivalent of the true name of the spirit and thus granted the magician a
measure of control over the beings.
A kameas (magic square) sigil.
A common method of creating the sigils of certain spirits
was to use kameas (magic squares) — the names of the spirits were converted to
numbers, which were then located on the magic square. The locations were then
connected by lines, forming an abstract figure.[1]
The use of symbols for magical or cultic purposes has been
widespread since at least the Neolithic era. Some examples from other cultures
include the yantra from Hindu tantra, historical runic magic among the Germanic
peoples, or the use of veves in Voudon.
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.[2]
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.[3]
A pinterest link for even more sigil ideas
Some Image searches and I found some somewhat common examples.
