Mage
Mage is an archaic term for magician. The term is popularly used among fans of role-playing games.Mages are the main difference between races in Warcraft and Warcraft II. They cast "spells" that augment your army or disable your enemy's. In Warcraft III they are known as "spellcasters".
An example of a "spellcaster" would be a Priest. They can heal your army, remove negative spells from your army, and increase the armor and damage output of your army.