Muad'Dib

Muad'Dib is a term with multiple applications within Frank Herbert's Dune universe.

Etymology
In Arabic, مؤدّب mu’addib means 'educator' "He who disciplines/teaches manners". Ad'dab or A'adaab are manners.

Glossary of Dune
In Terminology of the Imperium, the glossary of the novel Dune, Herbert provides the following definition: "MUAD'DIB: the adapted kangaroo mouse of Arrakis, a creature associated in the Fremen earth-spirit mythology with a design visible on the planet's second moon. This creature is admired by Fremen for its ability to survive in the open desert."

In addition to the moon, there is also a constellation called Muad'Dib in the sky of Arrakis; its tail points to the north, resulting in it being known as "The One Who Points the Way."

Paul-Muad'Dib
In Dune, when Paul Atreides is accepted into the Fremen he is given the secret "sietch name" (known only to his tribe) Usul, the Fremen word meaning "the base of the pillar." Paul takes "Muad'Dib" as his chosen name of manhood, to be used openly.

Stilgar explains why the choice of "Muad'Dib" pleases the Fremen: "Muad'Dib is wise in the ways of the desert. Muad'Dib creates his own water. Muad'Dib hides from the sun and travels in the cool night. Muad'Dib is fruitful and multiplies over the land. Muad'Dib we call 'instructor-of-boys.' That is a powerful base on which to build your life, Paul-Muad'Dib, who is Usul among us."

Paul is reluctant to throw away his full past and get rid of the full name his father gave him, which is why he first wishes to be called Paul-Muad'Dib. Also, he hopes that by keeping the name his father gave him, he can prevent the mass slaughter that will occur later in his name. Unfortunately, this name is soon forgotten by the Fremen and becomes simply "Muad'Dib", the messiah. The name of the prophet becomes breathing weapon in the leaps of the Fremen Mahdi Army.