Wizardry
See also: Discworld (world)#MagicThe title wizard is said to be derived from the archaic word "Wys-ars", meaning one who, at bottom, is very wise. In fact, the older wizards tend not to understand how magic actually works at all, instead relying on centuries of lore to achieve their effects. Younger wizards enthusiastically experiment, pushing back the boundaries of knowledge and making new discoveries about the nature of the universe. They don't understand how magic works either, but have much more exciting words to explain why not. These often invoke images of particle physics. The main issue is a generalized worry to where the power actually comes from and what sort of (often eldrich and downright monsterous) entities excessive use can attract.
An eighth son of an eighth son is automatically a wizard. When a wizard nears death – which they know some time in advance – he formally passes on his staff to a newborn wizard. If a wizard happens to have an eighth son, this child will be a "wizard squared" or "Sourcerer", as he generates his own magic and can therefore do just about anything with no effort. This is very dangerous, both because absolute power corrupts absolutely, and because it increases background magic levels considerably. Because of this, wizards generally lack children, due to both rigid celibacy laws and overall non-enabling personality. Besides a mention of Krull (see below) and the prominent Eskarina Smith, all wizards are implicitly male, though this may be a cultural bias of the Unnamed Continent confirmed by narravitium.
Wizards grade magical ability in a series of levels, the highest of which is eight. People without magical ability are "level zero". It was the opinion of many tutors at the time Rincewind was a student that he had a level that was possibly in minus figures, and that the overall magical potential of humanity would actually increase after his death.
Besides the UU, Wizard magic is known to be taught at Bugarup University in Fourecks (Archchancellor, Bill Rincewind) and Krull University in the secretive nation of Krull, as well as the recently-established Braseneck College in Pseudopolis.
Read more about this topic: Unseen University