The ‘Dune’ Dictionary

The universe of Frank Herbert’s Dune is famously dense, littered with a mishmash of terminology about as complex and varied as the languages J.R.R. Tolkien made up for The Lord of the Rings. Dune takes place thousands of years into humanity’s future, within a vast interstellar empire built upon the foundations of human history and that dates back millennia. The result is a lot of weird religious stuff, a lot of non-English words, and a lot of groovy psychedelic drugs.

In preparation for the release of Dune: Part Two, the second installment of Denis Villeneuve’s epic adaptation, we’ve compiled a reference guide like the chunky appendices in the back of every Dune novel. Come for a refresher on who’s who in the endless conflict between House Atreides and House Harkonnen, stay for a lengthy description of what “Kwisatz Haderach” actually means.

This dictionary may have minor spoilers, we suppose? This book is decades old.

Arrakis: The world in which most of the events in Dune take place; a desert spice planet. Arrakis is the third planet orbiting the star Canopus (a real star), possessing two moons, one of which has a giant crater in the shape of a human hand. Arrakis is habitable to a degree, supporting some human life as well as a number of local fauna, but it’s mostly made of endless plains of sand, giving it the colloquial nickname “Dune.” Arrakis is also the only place where you can mine spice, a hallucinogenic drug on which the entire interstellar economy is based. (These books were written in the 1960s.)

Atreides: One of 10 major Houses in the galactic-wide Corrino Empire that make up a sort of feudal U.N. assembly called the Landsraad, the governing body in charge of the imperial economy. Paul Atreides (Timothée Chalamet) is the young male heir of this House, meant to succeed his father, Duke Leto Atreides (Oscar Isaac). House Atreides is simultaneously popular in the galaxy and hated in the galaxy because of that very popularity. (In the Dune universe, being at all well liked makes you a target, and everyone is constantly trying to figure out sneaky ways to kill one another.) At the beginning of Dune, the Atreides are presented as the good, normal family fighting against the weird freaks. At the end of the Dune series, the last Atreides heir is himself a weird freak. Really makes you think!

Baliset: A nine-stringed zither-like instrument that is Dune’s version of a guitar. House Atreides’s war master, Gurney Halleck (Josh Brolin), is a fiend for the baliset, and word on the street is he plays a song or two in Dune: Part Two.

Bene Gesserit: The witchy order of highly trained, semi-psychic priestesses that not-so-secretly run basically everything in the Dune universe. They do this by using a combination of superhuman abilities, government infiltration, and religious manipulation. Duke Leto Atreides’s concubine, Lady Jessica (Rebecca Ferguson), is a Bene Gesserit priestess who ignited the ire of her sisterhood by changing the sex of her unborn child from daughter to son (they can do that) because she loved Leto so much. That son is born Paul, an outcome that essentially wrecks the centuries-long breeding program the Bene Gesserit had devised to create the all-powerful Kwisatz Haderach (see below).

The dealings of the Bene Gesserit are overseen by an extra-powerful Reverend Mother (Charlotte Rampling) who has access to the “genetic memories” of every Reverend Mother who came before her. An offshoot of the Bene Gesserit called the Missionaria Protectiva has spent the past few hundred years subtly preparing all of the planets in the empire for the coming of the Kwisatz Haderach by sowing mythology and prophecies into their respective religions.

Butlerian Jihad: The fanatical war waged against any and all “thinking machines” hundreds of years before Dune begins, and the reason why there are no computers in the Dune universe. Way before the events of Dune, the fledgling human space empire was taken over by man-made artificial intelligence, and the centuries of struggle against the machines led to a near-religious hatred and fear of computers in all forms. No one is even allowed to build computers anymore, according to one of the central tenets of the Orange Catholic Bible: “Thou shalt not make a machine in the likeness of a human mind.”

The Butlerian Jihad is in essence a plot device for Frank Herbert’s vision of a far-future society where everything is analog, and where the algorithmic and navigational computations that would normally be done by machines are instead done by drugged-up humans with ultra-enhanced cognitive abilities.

Crysknife: A Fremen weapon made of the tooth of a sandworm. Once unsheathed, the incredibly sharp and usually poisoned blade can’t be put away until it has drawn blood. Knives are the weapons of choice on Arrakis, since the use of guns or body shields would create vibrations that attract sandworms.

“Fear is the mind-killer”: The most iconic part of the Bene Gesserit’s Litany Against Fear, a mantra about controlling your body physically and mentally against outside stresses.

Fremen: The native humans of Arrakis, a desert-dwelling society that wages guerilla war against whichever noble House is mining spice from the planet’s surface. The Fremen are experts at navigating a dry, desolate world, and as such, water has become sacred to them—so sacred that when a person dies, they hook them up to a machine that sucks the moisture and blood out of their body and recycles it. Fremen live in underground communes called “sietches” and have kept their true numbers secret from the empire. They’ve also been waiting for the coming of the Kwisatz Haderach and are prepared to follow a proven leader to liberate their planet with fanatic devotion.

Gom jabbar: A deadly poisoned needle often used by the Bene Gesserit to test a person’s humanity—i.e., whether they were controlled by their instincts or by their mental awareness. “Gom jabbar” is also very fun to say out loud.

Harkonnen: The other major Noble House in the Dune universe, and House Atreides’s mortal enemy. The Harkonnens, stationed on their homeworld, Giedi Prime, are a brutal family of greedy bureaucrats and warmongers, overseen by their leader Baron Vladimir Harkonnen (Stellan Skarsgard), an enormous and terrifying villain who moves around using a hover suit. The Dune series begins with the Harkonnens’s reign over Arrakis being handed over to House Atreides, and the Harkonnens hate that.

Josh Brolin’s poetry: Josh Brolin wrote a bunch of poems about his Dune costars for a coffee table book about the making of the two movies. It’s called Dune: Exposures. Here is a very melancholy treatise on Timothée Chalamet’s youth:

Kanly: The practice by which two noble Houses officially and publicly feud with each other, with the end result being either a truce or the obliteration of one bloodline. House Atreides and House Harkonnen have been engaged in kanly since the Butlerian Jihad ended. Drama!

Kwisatz Haderach: “The Shortening of the Way,” a term derived from Hebrew (almost every non-English word in the Dune universe is derived from another language) referring to the prophesied messiah that would set the empire on the “Golden Path” toward a new enlightenment. Paul Atreides is proven to be the Kwisatz Haderach, possessing powerful precognitive abilities that allow him to see into the future, as well as his ability to use the powers of the Bene Gesserit, something men can’t do without going insane. The Fremen have their own words for this, inducing “Lisan al Gaib” from Arabic, meaning a foreign prophet, and “Mahdi,” also from Arabic, meaning “the one who will lead us to paradise.”

“May thy knife chip and shatter”: A threat used in Fremen pre-duel shit talk. It essentially means, “I hope your weapon breaks,” but its deeper essence refers to the Fremen practice of water preservation: If your opponent’s knife breaks, the duel will finish quickly, and less water (blood) will be wasted.

Mentat: A highly trained human computer whose mental abilities have been honed by discipline and psychotropic drugs. The mentats are used by the noble houses as advisers and calculators, and they’re used by the Spacing Guild (see below) to navigate their interstellar ships.

Movie theater: The place you’ll want to go to see Dune: Part Two. None of this “waiting for streaming” nonsense.

Muad’dib: The Fremen nickname for Paul Atreides, which is also their word for the hopping mouse found on the surface of the desert, as well as one of the moons that looks like it has a mouse-shaped mark on its visible side.

Padishah Emperor: The ruler of the human empire and master of the Known Universe. The Padishah Emperor at the time of the Dune series is Shaddam IV of House Corrino (Christopher Walken), who feels threatened by the popularity of the Atreides, using their beef with the Harkonnens to his advantage. The Padishah Emperor is protected by his own army of loyal Sardaukar, terrifying, bloodthirsty warriors who have their own war-centric religion.

Popcorn bucket: The vessel through which you will eat your popcorn if you see Dune: Part Two at an AMC theater. Fashioned to resemble the mouth of the iconic sandworm, the bucket requires you to stick your hand into a many-toothed opening—not unlike Paul Atreides sticking his hand into the Reverend Mother’s box of pain—which apparently feels about as good as it looks.

Sandworm: The famed local animals of the planet Arrakis. The giant sandworms are hundreds of feet long and patrol the desert, breaching the surface and eating anything tasty like a giant killer whale. Only the Fremen know that the sandworms aren’t simply an ecological nuisance—the worms create the spice that every House wants to exploit Arrakis to get. The creatures were inspired by the dragons of European mythology that jealously guard hordes of treasure. Fremen often ride the worms using “maker sticks” that fasten onto their bodies and keep them from diving under the sand.

Shai-Hulud: The Fremen term for sandworm, also derived from Arabic. To the Fremen, the sandworms are the physical embodiment of the god who created the universe, and so they are sacred. The Fremen also call them “makers,” referring to the sandworm’s ability to make spice. Bless the Maker and His water:

Spacing Guild: The organization of mutated humans and their ships that facilitate space travel. The Spacing Guild is secretly the society that controls everything else in the empire—without the Guild, no people or goods could get from planet to planet, the trade organization called CHOAM would collapse, and planet-bound fiefdoms would fall into isolation. The ships are flown through space by Guild navigators, humans that have been mutated beyond recognition to use spice for faster-than-light travel. Like the mentats, the Guild navigators are the result of the anti-machine crusade.

Spice: The most important substance in the universe. Spice, also called “melange,” is mined on Arrakis and taken as a drug to prolong the user’s life and give them higher physical and cognitive functions. For some, like the Bene Gesserit and the Guild navigators, spice gives the user precognitive abilities one can use to travel space or see into the future. Spice is highly addictive, and its users develop startling “blue-within-blue” eyes after prolonged use.

Stillsuit: The bodysuits used by the Fremen to walk around the desert of Arrakis. Stillsuits are designed to cover all parts of the body except the head to preserve the most water possible, constantly recycling the wearer’s bodily fluids—yes, they pee in the suits and then drink the pee. In the first movie, we see the Atreideses’ local guide, Dr. Liet Kynes, remark to Paul that he’s attached his stillsuit shoes “slip-fashion,” like a native would, despite never having set foot on Arrakis in his life.

Thumper: A device the Fremen use to summon a sandworm. Sandworms respond to any regular vibrations coming from the surface of the sand, like those given off by machinery or a person walking (that’s why you have to “walk without rhythm” on Dune), and a thumper makes a noise that can be heard by a sandworm miles away.

Voice: A special vocal timbre used by the Bene Gesserit to control the actions of another person, or to get someone to give information they otherwise would keep secret.

Water of life: The substance used in the “spice agony” that turns Bene Gesserit priestesses into Reverend Mothers. Taking the water of life involves drinking a liquid created by drowning a larval sandworm, and it’s lethal to anyone without the total mental and physical control of the most highly trained Bene Gesserit. In a Fremen sietch, when their Sayyadina (their own type of Reverend Mother) is close to death, another future priestess undergoes the spice agony to gain the Sayyadina’s genetic memories before they’re lost.

Emma Stefansky is a writer based in New York City who covers television, film, and books. Her work can be found in Vanity Fair, GQ, IndieWire, and Thrillist. Follow her on X @stefabsky.