po·​rous | \ ˈpȯr-əs How to pronounce porous (audio) \

Definition of porous

1a : possessing or full of pores
b : containing vessels hardwood is porous
2a : permeable to fluids
b : permeable to outside influences
3 : capable of being penetrated porous national boundaries

Keep scrolling for more

Other Words from porous

porously adverb
porousness noun

Examples of porous in a Sentence

The country has a porous border. a cleaner that should not be used on porous surfaces
Recent Examples on the Web By turns pleading and bitchy, mean and porous, Clare slithers around Irene’s sensitivities like a snake curious about the taste of its own poison. Hilton Als, The New Yorker, "Acting Black and White Onscreen," 22 Feb. 2021 The caves aren’t really caves but a 30-foot-tall, 150-foot-long sandstone cliff draped in curtains of ice, which is formed when water seeps out of and over the porous sandstone. Chelsey Lewis, Milwaukee Journal Sentinel, "Hiking to the Eben ice caves is a winter adventure in Michigan's Upper Peninsula," 18 Feb. 2021 The good news is that their next opponent, Sacramento, has the NBA’s most porous defense. Christian Clark, NOLA.com, "The Pelicans are getting crushed in crucial battleground — 3-point land," 16 Jan. 2021 Space becomes porous behind, around, and in front of the subject: a revolving-door effect, spinning pictorial depth out into the real world. Peter Schjeldahl, The New Yorker, "When a Museum Feels Like Home," 8 Feb. 2021 Li, Halas and their colleagues have built a solar desalination device with a porous plastic membrane that lets water vapor through but not liquid. Prachi Patel, Scientific American, "Sunlight Powers Portable, Inexpensive Systems to Produce Drinking Water," 26 Jan. 2021 The characters circle one another, their paths occasionally crossing, the boundaries between their lives porous but strictly controlled by law, the state, ideology and gender. Ilana Masad, Los Angeles Times, "Review: An American novel manages, for once, to get Israel right," 25 Jan. 2021 Allen was terrific on Sunday afternoon, getting into the lane seemingly at will against a mostly porous Washington defense and dropping off pass after pass for waiting teammates at the rim. Josh Newman, The Salt Lake Tribune, "Utah basketball’s latest loss tough to stomach, and Larry Krystkowiak didn’t hide it," 24 Jan. 2021 There were no shots over the top against a porous secondary and when the chances were there, Oregon didn’t even have the personnel on the field to take them in some instances. James Crepea | The Oregonian/oregonlive, oregonlive, "10 takeaways from Oregon’s loss to Iowa State in Fiesta Bowl," 4 Jan. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'porous.' 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 porous

14th century, in the meaning defined at sense 1a

Keep scrolling for more

Learn More about porous

Time Traveler for porous

Time Traveler

The first known use of porous was in the 14th century

See more words from the same century

Statistics for porous

Last Updated

27 Feb 2021

Cite this Entry

“Porous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/porous. Accessed 2 Mar. 2021.

Style: MLA
MLA Chicago APA Merriam-Webster

Keep scrolling for more

More Definitions for porous



English Language Learners Definition of porous

: having small holes that allow air or liquid to pass through
: easy to pass or get through


po·​rous | \ ˈpȯr-əs How to pronounce porous (audio) \

Kids Definition of porous

1 : full of small holes porous wood
2 : capable of absorbing liquids porous paper


po·​rous | \ ˈpōr-əs, ˈpȯr- How to pronounce porous (audio) \

Medical Definition of porous

1 : possessing or full of pores porous bones
2 : permeable to fluids

Keep scrolling for more

Comments on porous

What made you want to look up porous? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

February 2021 Words of the Day Quiz

  • squirrel in winter
  • Which is a synonym of perdure?
True or False

Test your knowledge - and maybe learn something along the way.

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

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