Enchantment
Enchantment is the imbuing of magical properties on objects or places, or the magical properties thus imbued. Essentially, any magical effect of lasting duration, even if that duration is only a few seconds, qualifies as an enchantment; single-shot effects such as fireballs and summonings do not. The creation of talismans is one notable form of enchantment, and the one perhaps that the word is most often used to refer to, but it also applies to temporary magical auras and effects, and to those affecting areas rather than discrete objects. Living creatures can also be enchanted, and often are, either with beneficial enchantments to give them special powers and boons or with malicious enchantments to bend their wills or transform their bodies.
Method
Any kind of magical process can lead to enchantment, though of course, as with everything about magic, the details depend on the arcanum. Many spells place enchantments upon their subjects—indeed, any spell with any sort of lasting magical effect does produce an enchantment, by definition. Likewise, many talismans or inherent powers of magical creatures can lay enchantments on their subjects. In many arcana, there may also be methods, involving lengthy rituals or alchemical processes, by which enchantments can be produced by those with no spellcasting abilities. It may be too that enchantments "bleed" into nearby objects and areas, or that repeated or long-term use of powerful magics may have a side effect of enchanting their surroundings or their contents, a phenomenon known as magical contagion. Spontaneous enchantment is also often possible, objects and places becoming enchanted under certain conditions even without the involvement (or the intentional involvement) of any living creatures or preexisting magics.
Removal
The removal or cancellation of an enchantment is known as cassation, and may be achieved by various methods. Most commonly, in many arcana a spell exists to revoke an enchantment, though such a spell may not be guaranteed to work; a more powerful enchantment may be more difficult to revoke, and a skilled mage may be able to put more power into it to make it more difficult still; or an enchantment may become more difficult to revoke as time passes and it becomes more entrenched (or, conversely, may become easier to revoke as its power fades). Rather than (or in addition to) a simple spell, the cassation of an enchantment may be possible by various rituals or other paracarminical means.
Some enchantments, generally produced by more complicated and time-consuming means, may be made not subject to ordinary methods of cassation at all. Such enchantments are called fixed, or indelible, in contrast to the delible enchantments that can be revoked normally. It's very possible, in some arcana, to have varying levels of indelibility—either the more effort put in to fix the enchantment, the harder it is to reverse; or possibly there are discrete levels of increasing indelibility that are achieved in different manners, or different types of indelibility which are revoked in different ways. An extreme case of a fixed enchantment is that on an eximium, which can often be removed only, if at all, in certain very difficult predetermined ways.
There may be other means by which enchantments end aside from revocation. A transient enchantment lasts only a predetermined amount of time before disappearing—as opposed to a persistent enchantment, which lasts indefinitely and is permanent unless revoked. Some enchantments may last a matter of seconds; others may last centuries; but as long as they have a fixed and finite duration, they are considered transient. A finite enchantment lasts only until sparked, or until it has been sparked some set number of times. After activating—or after it has fulfilled its quota of activations—it is gone forever. When the distinction is necessary, an enchantment which is not finite is simply called "non-finite"; those who refer to such enchantments as "infinite" may invite the scorn of the more knowledgeable.
In principle, any combination of delibility, persistence, and finity is possible. An enchantment which is both finite and transient, for instance, disappears after its duration has expired whether or not it has ever been sparked; an enchantment which is finite and persistent lasts indefinitely until sparked. Transient enchantments are usually delible, readily revokable before their duration is up, but it's also possible for a transient enchantment to be indelible, though in most arcana this is seldom done, if only because it's not generally worth the trouble to create a fixed enchantment that is going to expire on its own anyway. Indelible but finite enchantments exist on some talismans that can only be used once, or a particular number of times. However, in some arcana, certain combinations may be impractical or impossible. In some arcana, all enchantments may be transient (though possibly of very long duration), while in others the creation of a persistent enchantment is possible, but extremely difficult, which means fixed transient enchantments may be more common there than under other arcana. In some arcana, any enchantment made permanent is very difficult to remove, which means that there's no such thing in those arcana as a persistent delible enchantment—all persistent enchantments are fixed.
Discernment
Since enchantments may last for extended periods of time, methods have been developed of determining whether or not any enchantments are in place on an object or in an area, and to ascertain the exact nature of these enchantments. Such magical discernment may be achieved by use of spells, or by various paracarminical methods—and, of course, it's not out of the question for a creature to have an enchantment that allows it to discern enchantments. Magical discernment is not necessarily infallible; it may be inherently unreliable, or there may be various ways to misdirect it. Depending on the arcanum, different types of enchantment may require different methods of discernment, or different methods may be necessary for enchantments of different subarcana.
Types of Enchantments
Celemologists classify enchantments into several different categories, according to the nature of their subjects and how they are sparked. These category names are seldom used in non-technical speech or writing, the context usually sufficing to specify the type of enchantment. The different methods of categorization overlap; any combination of categories from the two methods is possible, with the obvious exception that since an auturgy can only be on a living creature, all auturgies must be epasmata, unless one ascribes to an extreme form of panempsychosis.
By Spark
Some enchantments have continuous effects that are simply always active, but many enchantments are quiescent until activated. The activating event is known as the "schasteria", or, less technically but much more commonly, as the enchantment's spark. The effect of a sparked enchantment could be instantaneous; it's quite possible for an enchantment to cause an object to shoot a bolt of electricity, for example, whenever anyone comes within ten meters, or when some other condition is met. Alternately, the spark may "turn on" a continuous effect, which thereafter remains on for some fixed duration (which may be permanent), or until "turned off" or altered into a different enchantment by a repetition of the same or a different spark. Regardless, the nature of the spark provides one convenient way of categorizing enchantments.
Auturgies
An auturgy is an enchantment that is sparked by the will of the person or entity the enchantment is placed on. It allows the enchanted being to make use of a particular power or give himself (or another) a particular property whenever he desires. This does not necessarily mean that the sparking of the enchantment is instantaneous, however, nor that there are no limits to its use. While both of these may indeed be the case, it may also be that sparking the enchantment takes considerable time and concentration, or that it can only be sparked a limited number of times, or a limited number of times within a given duration (such as three times per day), or that some time must be allowed to pass between activations—or that after the enchantment is sparked, some other criterion must be met before it can be sparked again.
Xenurgies
A xenurgy is an enchantment that is sparked by the will of a conscious being. If the enchantment is on a living creature, then it must be sparked by a creature other than the one enchanted, but much more commonly xenurgies are placed on inanimate objects. Xenurgies are subject to the same possibilities as auturgies regarding limitations to their use; furthermore, there may be additional conditions affecting what beings are able to spark the enchantment. It's common, for example, for a xenurgy placed on an object to be sparkable only by a person actually touching or holding the object, or even a particular part of the object (the haft of an enchanted weapon, for instance). Other xenurgies may be usable only by the "owner" of the enchanted item, with varying definitions of ownership.
It is possible for an enchantment to be sparkable both by an enchanted individual and by others. This is rare enough, however, that no word for it has entered the accepted lexicon—some celemologists call such an enchantment a "tinurgy", a "xenauturgy", or a "panturgy", but none of these terms is in common use.
Hyspleges
A hysplex is an enchantment which is sparked by the fulfillment of some condition, other than the will of a living creature. The condition could be almost anything; a hysplex could be sparked by the speaking of a certain word (whether or not the speaker intends to spark the enchantment, or is even aware of it), or by the presence of a certain type of object or material, or by the time of day or of the year. Some celemologists further subdivide hyspleges into smaller categories in various ways:, by whether the spark involves time, or movement, or sound, or abstract conditions; whether the sparked enchantment becomes permanent, or lasts for some duration, or continues until deactivated; or by various other criteria. None of these subcategorical systems has yet attained anything resembling universal acceptance, however.
Enchantments sparked by gestures or by the vocalization of magic words are usually considered hyspleges, though some celemologists classify them as a sort of xenurgy (or auturgy, depending on whether the enchantment responds to the words or gestures of the enchanted creature or of other creatures).
Aeiurgies
An aeiurgy is an enchantment that is continually active. An aeiurgy has no spark, or, equivalently, the very act of creating the enchantment doubles as the spark; aeiurgies are not necessarily permanent, but at least while they are operative their influence is continuously in effect. Common aeiurgies placed upon objects include those of strengthening and durability, multum in parvo, and glows and other cosmetic effects; upon creatures various forms of thelxis, agalmatation, and transfigurement, as well as enchantments of protection and enchancement of abilities. Illusions cast on areas are often aeiurgical as well. In principle, however, nearly any enchantment may be aeiurgical, though some effects lend themselves to aeiurgy better than others. (Naturally, since aeiurgies have no sparks, they cannot be finite enchantments.)
Enchantments causing momentary effects that fire repeatedly—such as an enchantment that causes an object to fire off a ray of intense heat every five minutes—most celemologists consider to be aeiurgies, but some view them instead as hyspleges with the "spark" being the passage of the appropriate interval of time. In any case, the distinction is entirely academic, and has, of course, no effect on how such enchantments function.
By Subject
Enchantments are further categorized by the subject on which they are active—be it an object, an area, or an entire plane or cosmos. Generally, the types of enchantments applicable to one of these types of subjects are sufficiently different from those applicable to others, and the way the enchantments work is sufficiently distinct, to make this categorization useful, though there are some enchantments that may work similarly on different classes of subject.
Epasmata
The most common kind of enchantment (on most worlds) is the epasma, an enchantment placed upon a single discrete object, or a group of objects. In fact, generally when an enchantment is spoken of, unless specified otherwise it's an epasma that's meant. Some celemologists reserve the word "epasma" to refer to enchantments placed on nonliving objects, and use the word "epode" to refer to those placed on living creatures. Functionally, however, it makes little difference (again, on most worlds) whether the object of an enchantment is living or nonliving, and most celemologists do not make that distinction.
An object with a fixed epasmatic enchantment upon it is known as a talisman, though often that word is reserved for small, portable objects. Any object can be enchanted and made into a talisman; weapons and jewelry are particularly common, but enchanted clothing, buildings, and objets d'art also exist, among innumerable other possibilities.
Rhegi
A rhegus is an enchantment on a volume of space, rather than on a specific object—although the volume of a rhegus may very well be defined relative to an object, such as in a five-meter radius around an object, or a three-meter radius centered ten meters above the object. Alternatively, it may be defined absolutely, or relative to a stationary object, which has a similar effect. The volume of a rhegus may be arbitrarily small, but it may also be very large; rhegi covering entire nations and continents are not too uncommon, and any area referred to as "enchanted" (such as an "enchanted forest") probably is covered by a rhegic enchantment.
Hapantics
There are some enchantments that are active throughout a plane, or even a cosmos. Known as hapantics, these enchantments may be thought of as simply a part of the nature of magic where they are active, and make up an accepted component of how things work. If little known, however, a hapantic may compose a useful magical "loophole" exploitable by those aware of its existence. Naturally, hapantics are powerful magics, and not generally easily produced (nor easily revoked); the creation of a hapantic enchantment may be beyond the capabilities of many gods, and though perhaps some extremely powerful mages may be capable of such a feat, and some eximia may facilitate it, normally a new hapantic is the product only of some extraordinary conjunction of magics leading to an earthshattering event. Of course, as with most absolutes, there may be exceptions; it could be that under some arcana, the creation of a new hapantic is a much simpler feat.