reverse osmosis

American  

noun

Chemistry.

1. the process in which pure water is produced by forcing waste or saline water through a semipermeable membrane.

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reverse osmosis British  

noun

1. a technique for purifying water, in which pressure is applied to force liquid through a semipermeable membrane in the opposite direction to that in normal osmosis

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reverse osmosis Scientific  

1. A method of producing pure water by forcing saline or impure water through a semipermeable membrane across which salts or impurities cannot pass. Reverse osmosis is used for water filtration, for desalinization of seawater, and in kidney dialysis machines.

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Etymology

Origin of reverse osmosis

First recorded in 1950–55

Compare meaning

How does reverse-osmosis compare to similar and commonly confused words? Explore the most common comparisons:

• osmosis vs. reverse osmosis

Example Sentences

Traditional desalination methods such as reverse osmosis and thermal distillation can be expensive and energy intensive.

From Science Daily • May 31, 2026

Pitcher filters are simple, but their long-term cost can be higher than that of adsorption or reverse osmosis filters installed under the sink.

From Salon • Oct. 3, 2024

“Typically, for metals, reverse osmosis is the best option,” said Campbell.

From Los Angeles Times • Jul. 22, 2024

The membrane-based system, also known as reverse osmosis, works by pushing saltwater through a semi-permeable membrane, which catches the salt.

From BBC • Nov. 5, 2023

Microfiltration, reverse osmosis, ultraviolet radiation, and abracadabra—they turned the county’s last day of raw sewage into nearly fifty thousand gallons of drinkable water.

From "Dry" by Neal Shusterman and Jarrod Shusterman