Palantir was Sindarin Elvish for "Far See-er." In the books the Palantirs functioned as both radios (communicating with each other), and radars of sorts. They would show the user events at different points in both space and time, although it was hard to tell where and when the events you saw took place. In the books, Denethor had a Palantir which he hoped to use to protect Gondor, but Sauron (being far more powerful) easily used his Palantir to make Denethor fatalistic, paranoid, and degenerative (which was why he behaved the way he did in the books and movie).

Mithril is also Sindarin Elvish for "Gray Glitter" and describes its appearance. It was virtually indestructible, and was the obvious inspiration for other McGuffin super-metals in fiction.