What is "runecaster"

The runecaster or runepriest is a playable character class in the Dungeons & Dragons fantasy role-playing game. The runecaster appeared in multiple forms in second edition and third edition and as the runepriest in fourth edition, with rune magic also appearing in other editions of the game. The runecaster has been implemented as a warrior or fighter class, an arcane or wizard class, and a divine or priest class as well as a set of options for including rune magic without need of a specialized class. While rune magic is found in all editions of Dungeons & Dragons, at least as spells, specialized runecasters have not appeared as classes or class-like options in every edition.