Gandalf is the fictional wizard known as Mithrandir in J.R.R. Tolkien’s writings.
Mithrandir is a Sindarin name meaning “Grey Pilgrim,” one of several names used for Gandalf in Middle-earth. He is also called Gandalf the Grey and later Gandalf the White, reflecting a major transformation during The Lord of the Rings.
Gandalf belongs to the Istari, spiritual beings sent to Middle-earth in the Third Age to oppose Sauron. In his familiar form he appears as an elderly wanderer, but his nature is closer to that of a Maia than an ordinary human wizard.
The name is sometimes confused with other titles. Saruman is the White Wizard and the head of the Istari before his betrayal, while Radagast is another wizard associated with animals and the wild. Mithrandir specifically refers to Gandalf.