Bondeds: A magical animal or animals who become so close to a human or other magical beings that they 'bond', meaning their minds and spirits are forever linked.
Paladin: Magical beings made up of elemental magic (fire, earth, water, air and quintessence). Extremely powerful. In order for mages to achieve Level 2, they have to bond with a paladin.
Mage: A mage is a being, most commonly human, with a special magical gift. They come in five different types, related to the five elements: fire, water, earth, air and quintessence. It is as of yet unclear whether all healers are water, all warriors are earth, etc., or if it varies from mage to mage. Although, in Legend of the LAOA, Tasha states that Sierra has Healer-type Magic with some Warrior as well, both under the Fire Element, which implies that it does in fact vary from mage to mage.
Magic Levels: Magic levels are the ranks a mage goes up before they reach full power. To truly achieve the first level, a mage usually needs a power stone and at least one bonded animal (Emily is an acception to the latter). To achieve the second rank, the mage must bond with a paladin, a creature with strong elemental magic the same as their own element. The third level is still unknown (it was stated in Ghost Wolf that there were only three levels), except that it allows mages to become masters of their elemental magic. Each time a mage goes up a level, their jewel changes color and becomes much, much stronger and much more powerful, yet harder to control, therefore greatly strengthening and increasing their magical powers and abilities to innumerable uncontrollable levels.
Portal: A large wide whitish blue circular doorway between planets, worlds and dimensions.
Magic Jewels: Magic Jewels are created by compressed magic, magic jewels help focus a mage's unique magic. Without a magic jewel, the magic will never quite work out as was intended, and could cause chaos.
Web of Magic: A web on the magical plane of existence, connecting all worlds with each other through portals. In Ghost Wolf, the Dark Sorceress explains that the fairy map, a map of the Magic Web, only reveals a small part of it, and says that the entire Web is impossible to map. However, it is apparently not impossible because it was done and the Spider Witch possesses a map of the entire Web.
Power Crystals: Crystals that contain magic from Avalon. There are about nine of them, however one was accidentally destroyed by Kara. Can either contain light magic or dark magic.