Olorin/Gandalf. Olórin, being the wisest of Manwë's maiar, was sent to aid the last of the free peoples of Middle Earth in the third age. He was sent in the form of an old man wizard, who was called Gandalf.
The name Gandalf derives from the Old Norse words gandr (magic staff) and álfr (elf), thus a protective spirit who wields a magical wand. In Valinor he was known as Olórin, which comes from the Elvish 'olor', which means “dream”, although “that does not refer to (most) human ‘dreams,’ certainly not the dreams of sleep". Furthermore, olor is derived from Quenya olo-s which means “vision, phantasy.”