Gandalf, p.n. 1. Gandalf Greyhame, wizard protagonist of LOTR; also Gandalf the Grey, Gandalf the White, Incánus, Mithrandir, Olórin, Tharkûn, The Grey Pilgrim, Stormcrow. 2. in gamerese, can refer to any mage character, particularly one with Gandalf-like features: grey robe, giant pointy hat, tall magic staff, long white beard, and a predilection for very short hairy men. [GJ1]
Addendum: "Gandalf" means "wand elf," and was the name of a dwarf (Gandálfr) in the Gyfaginning, part of the Prose Edda of Snorri Sturlson [GJ1]