In Frank Herbert’s novel Dune, the protective desert suit is called a stillsuit.
Designed by the Fremen of Arrakis, the stillsuit is a body-enclosing garment that conserves nearly every drop of moisture. It captures perspiration, urine, and water vapor from breathing, then filters that moisture for drinking. Movement and breathing help drive the suit’s pumping and filtration systems.
The stillsuit is essential because Arrakis is an intensely dry world where exposed people can lose many liters of water each day. Water is therefore sacred to the Fremen, and reclaiming moisture is both a survival technique and a central part of their culture. A Fremen’s stillsuit must fit correctly and be properly maintained; a damaged or badly worn suit can be fatal.
A common mix-up is treating “Fremen garb” as the suit’s official name. Fremen clothing includes other desert gear, but stillsuit is the specific canonical term. The concept first appeared in the 1965 novel and has since become one of Dune’s most recognizable pieces of fictional technology.