Magus

In the old legends of the middle east from where they orginate, the Magus, or Magi, are studiers of the arcane who also study other arts such as the sciences, astrology, and alchemy. They were overall then studiers of knowledge, which is perhaps why the word Magi tends to conjure the idea of mystery, knowledge and wisdom in the minds of people when they hear it.

The word and ideas being the Magus are used in a variety of fantasy settings, usually as a kind of magic user with skills beyond the normal arcane.

Pathfinder

In the pathfinder setting a Magus is a bit different to the traditional sources. They are studiers of the arcane and the martial arts, bending spellcraft and weapons work together into a fusion deadlier then it's parts. They are often travellers seeking mystic and material lore to further improve their skills. Think of high elf loremasters from Warhammer Fantasy or Elrond from Lord of the Rings and you will have a close idea to what this class is.