Magic is a dead cat in an oil-stained burlap bag. Magic is a smelly old man, despised but feared by his neighbors. Magic is what the king turns to, when his soldiers fail. --- a long-dead wise man of Areth Pirn
Magic is the dark art by which events are influenced outside of the normal boundaries of cause-and-effect. Rather than the glamorous ideal of shining wizards casting powerful fireballs at wicked foes, the reality of magic instead tends to be base, tedious work which earns few friends.
Hated and feared, the magician pursues his craft out of the sight of men. Like wisps of smoke rising from an ember cast into dry straw, so the mage's spells slowly take hold, woven with secret knowledge and foul ingredients.
The casting of a magical spell is accomplished with three ingredients: Knowledge of the spell, possession of any items necessary to fuel the spell, and a sufficient level of magical aura to perform the ritual or ceremony.