Magician

A Magician (魔術師) is a person who is trained to use magic. A 'normal' person can also use magic, as Tsukuyomi Komoe demonstrated in the 1st story arc of the anime and the 1st Light novel, though a normal person will suffer more severe consequences than a magician if they fail. At one point, Index states that people without "mana" cannot use magic, such as herself. However, the term "mana" wasn't defined.

It seems that the Espers concentrated in Academy City are blissfully unaware of the existence of magic users, since Shirai Kuroko mistook Sherry Cromwell as a Power User when the latter summoned a golem. Magicians are typically distinguished from Espers due to the former's use of items with occult properties

Western magicians carve their sorcery name onto their souls. Their sorcery name is normally the reason they took up magic, or the one dream which they would sacrifice their life for. An exception are Saints, who may carve it onto their chest/heart instead, as shown by William Orville. Stiyl Magnus once said the real reason for having sorcery names is long forgotten, now it is only used in battle as a gesture to say 'it will now be a fight to the death'.

Western Magicians since the end of the 19th century, according to Tsuchimikado Motoharu, are beings that "whose wishes are not fulfilled, whose prayers to God went unanswered - people who have lost their way and turned towards this back door called Magic". According to him, most magicians are like children in the aspect they fight honorably and let emotion cloud their judgment - whereas other professionals such as soldiers will shoot without remorse; magicians are like "Children who hold knives. And also as Children who have been betrayed by the world, trembling and crying at the same time". As such, magicians have very little loyalty to organizations - they are willing to betray the group to which they are affiliated to if it somehow clashes with their own dreams/goals.

Western magicians dabble in a multitude of skills to do with magic, such as alchemy, astronomy, and summoning. Aureolus Izzard was called a 'Alchemist' because that was all he was good at out of the myraid of sub-sets of magic. In Index canon Alchemy in general is useless compared to other magic, and was renowned for being a trick for gullible nobles in the 16th century where they believed turning lead into gold was possible. Ars Magna was a exception in that it held exceptional power.

魔神Majin or "Magic God" the highest possible position available to magicians where the magic of the user is almost considered divine. Other positions is possibly above that, such as 'Saints' or 'One Who is Above God (Kamijou)', but they cannot be reached by 'normal' magicians and depends almost entirely on factors like talent or birth.

Other magicians (like the Etzali of the Aztecs) might not follow the Western rule of sorcery names, or became mages for the same reason.