Gandalf's body was mortal, subject to the physical rules of Middle Earth, but his spirit was immortal, as seen when he died as Gandalf the Grey and resurrected as Gandalf the White.
Le corps de Gandalf est mortel, soumis aux lois physiques  de la Terre du Milieu mais son esprit est immortel, comme on le voit lorsque Gandalf le Gris meurt pour renaître en Gandalf le Blanc.