semi·​per·​me·​able | \ ˌse-mē-ˈpər-mē-ə-bəl How to pronounce semipermeable (audio) , ˌse-ˌmī-, -mi- \

Definition of semipermeable

: partially but not freely or wholly permeable specifically : permeable to some usually small molecules but not to other usually larger particles a semipermeable membrane

Keep scrolling for more

Other Words from semipermeable

semipermeability \ ˌse-​mē-​ˌpər-​mē-​ə-​ˈbi-​lə-​tē How to pronounce semipermeable (audio) , ˌse-​ˌmī-​ , -​mi-​ \ noun

Examples of semipermeable in a Sentence

Recent Examples on the Web The second is whether the virus can gain access to the brain, which is protected by a semipermeable barrier that can block out pathogens and other harmful particles while still allowing nutrients and other key molecules to make it through. Los Angeles Times, 5 May 2021 These cytokines are seemingly able to cross the semipermeable network of capillaries that connect the brain to the rest of the body (known as the blood-brain barrier). Claire Maldarelli, Popular Science, 22 Feb. 2018 Well, egg shells are semipermeable, and the older the egg, the more air can get through the shell, which explains why old eggs float. Kelsey Hurwitz, Woman's Day, 2 May 2020 The process of moving water across a semipermeable membrane is called osmosis. Svenja Lohner, Scientific American, 9 Jan. 2020 By pumping the positive ions—like sodium or potassium—to the other side of a semipermeable membrane, researchers can create two pools of water: one with a positive charge, and one with a negative charge. Robert F. Service, Science | AAAS, 4 Dec. 2019 The semipermeable membranes were sheets of purple celluloid Gonzaga students had ordered from England, 135 square yards of it, at a cost of $300. John Kelly, Washington Post, 5 Aug. 2019 These scientists employed a transparent capsule, made up of a semipermeable resin membrane and filled with water, to capture CO2 and then transform it into CO thanks to a light absorber coated with catalysts. Javier Garcia Martinez, Scientific American, 26 June 2017 Made from cellular material extracted from plants, the semipermeable film adheres to the outside of the avocado and slows the rate at which the avocado loses water and carbon dioxide and absorbs oxygen. Caitlin Dewey,, 19 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'semipermeable.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of semipermeable

1888, in the meaning defined above

Keep scrolling for more

Learn More about semipermeable

Time Traveler for semipermeable

Time Traveler

The first known use of semipermeable was in 1888

See more words from the same year

Statistics for semipermeable

Last Updated

11 May 2021

Cite this Entry

“Semipermeable.” Dictionary, Merriam-Webster, Accessed 13 Jun. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

Keep scrolling for more

More Definitions for semipermeable


semi·​per·​me·​able | \ ˌsem-i-ˈpər-mē-ə-bəl, ˌsem-ˌī- How to pronounce semipermeable (audio) \

Medical Definition of semipermeable

: partially but not freely or wholly permeable specifically : permeable to some usually small molecules but not to other usually larger particles a semipermeable membrane

Other Words from semipermeable

semipermeability \ -​ˌpər-​mē-​ə-​ˈbil-​ət-​ē How to pronounce semipermeable (audio) \ noun, plural semipermeabilities


Test Your Vocabulary

Name that Thing: Dog Breeds

Spell It

Can you spell these 10 commonly misspelled words?

 AlphaBear 2

Spell words. Make bears.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!