'Dune' Glossary: All the Terms Used and What They Mean

Frank Herbert's "Dune" novels feature a number of complex languages and phrases used throughout the story.

There are many planets, cultures and religions included in Herbert's story, and Dune director Denis Villeneuve remains true to the source material and includes the terms with little explanation of what they mean.

Given the complexity of the language of Dune, Newsweek have collated a glossary of all the terms and phrases you might have missed.

Bene Gesserit

Paul's mother Jessica (Rebecca Ferguson) is a member of the Bene Gesserit, an ancient all-female religious group who use their influence on the Imperium and the Known Universe to put humanity on what they deem is an enlightened path.

They have superhuman abilities thanks to intense physical and mental training, and one such power is the Voice which allows them to control others and force them to do their bidding.

As well as Lady Jessica, Dune features the Reverend Mother Mohiam (Charlotte Rampling) who is a leader of the order with enhanced powers.


A Crysknife is a sacred knife used by the Fremen and is made from the teeth of a dead sandworm.


The Fremen are the native people of the planet Arrakis who have adapted to the harsh desert climate and have created a vast amount of technology to help them survive it.


A Fremkit is a pack designed by the Fremen to help them survive for weeks in the desert of Arrakis, it includes a water-saving Stilltent and a thumper to draw away the attention of sandworms if needed.

Gom Jabbar

The Gom Jabbar is the name of a poisoned needle used by the Bene Gesserit, and in Dune's case by the Reverend Mother, to test the humanity of an individual.


A Hunter-seeker is a small, almost undetectable tool that is used by assassins to kill their targets and can be operated from afar.

It floats in the air and is shaped similarly to an insect, it kills a target by injecting them with poison from a tiny needle.

Kwisatz Haderach

The Kwisatz Harderach is a term used by the Bene Gesserit to describe a male member of the order whose mental abilities allow him to bridge space and time.

The phrase means "Shortening of the Way", and the reason only a man can be the Kwisatz Haderach is because the Bene Gesserit's powers only allow women to access memories from their maternal side as they have two X chromosomes.

A male Bene Gesserit has access to both X and Y chromosomes and can therefore access the genetic memories of all his ancestors, while spice melange will give him the ability to look into the future.

Lisan al Gaib

Lisan al Gaib is the Fremen prophecy that foresees a Messiah-like figure who will come to Arrakis from off-world.

He is prophesised to lead the Fremen to a bountiful planet, and in the Fremen language the term translates to "The Voice from the Outer World."


Paul Atreides (Timothée Chalamet) is frequently referred to as Mahdi in Dune, which is a Fremen word for the savior featured in their messianic legend the Lisan al Gaib.

The term Mahdi translates to "The One Who will Lead us to Paradise."

Dune press still
Dune press still
Dune press still


In the novels Paul adopts the Fremen name Muad'Dib, which is also the name for a desert mouse found on the planet Arrakis.

Missionaria Protectiva

The Missionaria Protectiva is the Bene Gesserit's quest to spread superstition, myths and prophecies to other, primitive cultures in order to later control and take advantage of them.

One such legend created by the order is the Lisan al Gaib which prophesies that the son of a Bene Gesserit woman will lead the Fremen to freedom.


The Sardaukar are a group of soldiers who are fanatically loyal to the Padishah Emperor, the ruler of the Imperium and the Known Universe.

They were trained from infancy to fight, and they have a ruthless and cruel fighting style that makes them one of the most feared military units in the universe.

Shai Hulud

The Fremen have a sandworm deity who they refer to as the Shai Hulud, or the "Old Man of the Desert'.

On Arrakis the sandworms grow to huge sizes and can live for decades, and the Shai Hulud is the greatest of them all.


A Stillsuit is one of the inventions made by the Fremen to survive the Arrakis desert, it is a suit that preserves the wearer's water (from their sweat, breath, tears etc) and recycles it so it is drinkable.

Spice Melange

Spice Melange, commonly known as "spice", is a narcotic substance that is mingled with the sand on Arrakis.

Spice gives a person the ability to expand their consciousness, in Paul's case he sees visions of the future for example, and it also have long-standing health benefits.

Those exposed to spice for long periods of time end up with eyes that are stained blue.

Tahaddi Challenge

When a Fremen wants to challenge a person to mortal combat over a particular issue, like questioning their leadership, they will issue the Tahaddi Challenge.

It is a fight to the death between the challenger and the person they challenge, or their champion if they are unable to fight.

Dune is out in cinemas and on HBO Max now.