It’s a bit of a pet peeve of mine when people badly use terms in an occult context.  To be fair, different traditions may use certain terms in particular ways that are specific to that particular tradition, which may or may not differ from normal use.  Other groups treat some terms completely interchangeably when, strictly speaking, the terms signify different things.  Generally, however, there’s not much rigor in how people use specific terms, and end up misusing them (through their own ignorance and confusion) or abusing them (to intentionally mislead or annoy others).  I’d like to clear up a few things and offer some of my definitions for particular terms used in an occult context, this time focusing specifically on terms used for different types of symbols.

For any of these terms, “symbol” is the highest-level term I can think of for any of these following terms.   If you’re not sure what kind of symbol a particular thing is, just say “symbol”.  Everyone understands that.  Not everyone understands what a particular person means by “sigil” or “rune”, however.  Granted, these words are given with my personal definitions, and again, may not be those used by other traditions.  However, for the sake of having a regular inventory of words with specific, unambiguous meanings, here’s how I use these particular things.

Glyphs are symbols used to indicate a basic thought or sound.  In other words, a glyph is much like a written-down word.  Individual letters communicate sounds; individual numerals communicate numbers; individual Chinese characters communicate sounds or concepts or words; the glyphs for the planets, zodiac signs, elements, and alchemical concepts communicate those things and only those things.  Glyphs are essentially a generalized notion of a letter in an alphabet; they are characters in a writing system that includes letters, numbers, punctuation,  labels, and so forth.  Glyphs may or may not be used in an occult context; for instance, these words you’re reading right now are composed of glyphs (letters and punctuation of the English alphabet), but so is an astrological chart (the symbols used to denote the planets and Zodiac signs) or a computer science textbook (punctuation and numerals and diagrams to indicate logical connections or mathematical operations).  Glyphs may be used one at a time (using the symbol for the Sun) or in combination with other glyphs (multiple letters to spell out a name).

Seals are symbols that are invented as a complete unit or are received from a spirit.  Seals cannot be decomposed into more basic things, but are a whole unto themselves.  They are symbols that are not generated according to a particular rule or composed according to sacred geometry.  They are simply abstract symbols that refer to something.  Importantly, especially in my own work, seals are “revealed” or given unto someone by a spirit or person to refer to themselves; seals are an abstract “body” to give an idea a graphical or visual form.  Consider the symbols used to refer to spirits in the Lemegeton Goetia; these are not composed of more base units or other symbols, but are whole things unto themselves.  These are seals, and often have no origin besides “this is what I was shown to use and has no rhyme or reason beyond that”.  Seals are to constructed diagrams what barbarous words of power are to words in the dictionary; they may not have any communicable meaning that us humans can understand, but they work.

Sigils are symbols that are constructed according to a particular algorithm.  Think of the standard way of creating a letter-based sigil according to Agrippa (book III, chapter 30) or as used in modern chaos magic, or like with my own shorthand system.  Alternatively, consider the sigils used for the planets with their planetary intelligences and spirits from Agrippa (book II, chapter 22), which are lines drawn over the qameas of particular planets and playing connect-the-dots with the gematria values of individual letters of a name or word.  Sigils are symbols created according to a defined set of rules (combine these letters, connect these numbers on this qamea, etc.).  They are not always artistically made, although the algorithms used to generate a sigil may have some leeway for style and innovation.  A painting may incorporate sigils, but a sigil is not made of pictures; a sigil is a geometric, abstract form composed or generated from glyphs.

Runes are letters of the writing systems used for Germanic languages prior to the introduction of the Roman script.  In other words, runes are no more than letters of a particularly old style of European alphabet.  These can be classified, generally speaking, into two families: the Scandinavian futhark (both Elder and Younger, together used between the 2nd and 11th centuries) and the Anglo-Saxon futhorc.  There were medieval runes used in some astrological contexts, but generally runes stayed out of Hermetic and Western ceremonial stuff.  However, a particular alphabet known as Darlecarlian runes was in use until the 20th century in a small province in Sweden, but this was certainly the exception to the historical abandonment of runic writing.  There are other systems of writing and symbols that are runiform, such as Old Turkic and Old Hungarian, but these bear only a superficial resemblance to Germanic runes, and are not technically runes on their own as they belong to a different writing system, culture, and geographic area.

Pentagrams are five-pointed stars.  That’s it.  Nothing more than that.  You can only really draw a pentagram one way, regardless of orientation.

Hexagrams are six-pointed stars . Again, nothing special here, but there’s a bit more complexity.  The Star of David is nothing more than a hexagram composed of two overlapping equilateral triangles, which is what’s usually meant by “hexagram”.  The unicursal hexagram is another type, though it’s not original to Crowley by any means; the mathematician Blaise Pascal depicts it in one of his works from 1639.  The “elemental hexagrams” shown in the Key of Solomon (book I, chapter 3) are not, strictly speaking, hexagrams (with the exception of one); they are configurations of two triangles each that do not, necessary, combine to form a proper hexagon.

Pentacles are not stars.  They are not necessarily pentagrams, nor are they necessarily hexagrams.  Pentacles are more of a system of symbols that work together in unison for a particular goal; they are something usually, but not always, more elaborate than a sigil and are not necessarily combined in an algorithmic way.  Consider the pentacles from the Key of Solomon (book I, chapter 18), or the Elemental Weapon of the Earth as used in the Golden Dawn, or the protective lamen with the pentagram and extra symbols used in the Lemegeton Goetia, or that used in the Heptameron of Pietro d’Abano.  Pentacles are, essentially, the physical version of a graphic design composed of one or more symbols, often including letters and names, and arranged in a method more akin to sacred geometry than algorithmic combining or tracing.  Pentacles are tangible objects, things you can hold and touch and wear.  All pentacles are talismans, although not all talismans are pentacles.  For instance, a talisman engraved in a circular stone may have the design of a fish surrounded by Hebrew words can be considered a pentacle, but a talisman of a stone fish with words engraved on it is not a pentacle.  Pentacles are generally round, flat objects such as a circular piece of paper or a metal disc that have a design engraved, painted, drawn, or otherwise inscribed upon it as a graphic design of a system of symbols.  Pentacles are not oddly-shaped things like carved statues or rings or wands, despite its talismanic properties or designs on them.  Although the words “pentacle” and “pentagram” are related and were originally used interchangeably, the word “pentacle” started to be used for any magical talisman in the form of a pentagram or hexagram starting in medieval French.  An alternate etymology combines this with an older French word for pendant, pentacol or pendacol, or something worn around the neck.  Indeed, most pentacles are typically worn around the neck as lamens, which is probably the most correct use of this word in my opinion, but can easily be expanded to other (typically circular and flat) objects with a system of magical symbols inscribed upon it.

Tetragrammaton (more properly the Tetragrammaton) is another word for the four-letter name of God, Yod-Heh-Vav-Heh or Yahweh or Jehovah or whatnot.  The word is Greek and literally means “the thing of four letters”.  It is a title to refer to the sacred name of God, akin to the Hebrew haShem “the Name”, but is often used in Hermetic and Solomonic work as itself as a sacred name of God.  However, this is nothing more than a word composed of individual letters; the word “Tetragrammaton” does not refer to any pentacle or other occult design.