I want to distinguish between two types of magician. I'm going to provisionally name them magipraxists and magiologists, and my request is for more familiar terminology to replace my invented and silly-sounding words.
Magipraxists are what you probably think of as a magician, in that they perform acts of magic. They cast spells, summon demons, enchant objects, and so forth. Some act essentially as outlaws, taking what supplies they need by force; others make a living performing utilitarian magic for paying customers and purchasing needed supplies; still others are employed on retainer by politically powerful individuals with access to repositories of supplies. Not all persons are capable of performing magic; in addition to the physical implements, one requires a degree of hereditable ability and substantial training.
Magiologists study magic, and may, if able, perform it in controlled settings to further their understanding. In ages past they would try to keep their discoveries secret and gain some proficiency in magipraxy to commercialise their discovery, as a middling magipraxist applying cutting-edge magiology could often outcompete rival superior magipraxists relying on outdated magiology. But there is a sense that recent discoveries have tended to be smaller improvements with narrower applicability, and therefore modern magiologists act more like professors, working collaboratively at facilities where they divide their time between research and teaching future magicians (some students going on to become magipraxists and others magiologists).
What would you call these? I'd be okay with using "magician" for magipraxists if I had a comparably widely recognised word to use for magiologists. No post I was able to discover on this site offered any helpful terminology; there is a lot about the use of magic to confound or assist in conventional sciences, but little about the science of magic itself.
Some flavour to help illuminate the relationship between the two:
Magipraxists regularly summon demons from five alternate realms of existence to perform tasks for them. Magiologists have made contact with a sixth, but it is a two-step process which requires traversing the third one; the environment of the third is lethal to the inhabitants of the sixth, so it is not a viable route for summonings. Further magiological research has established eight as the upper bound on the number of such realms, although the actual number is not known. Magipraxists complain about funding these ivory-tower magiologists who produce such useless results.
Magipraxists learn how to cast weather-affecting spells using stones of a variety of types. These stones usually have natural origins, but magiologists devised methods to synthesise some. Most notably, invoking a fog no longer requires rare heirloom-quality mined stones but can be accomplished with common and cheaply available synthetics. Magipraxists who own mined stones feel unfairly cheated of value by the magiologists, while those who have since purchased synthetics view this development positively.
Magipraxists are employed to enchant various objects, but a spell that confers strength on one material may embrittle another. Magiologists work with structural engineers to ensure that magically-strengthened pieces will not cause harm to nearby parts of the structure. An inquiry into a bridge collapse has divided magicians; the magipraxists have endured criticism of the quality of their spellcasting in its construction, while questions have been raised about the magiologists' claims as to the compatibility of the spells involved.