porous
Americanadjective
-
full of pores.
-
permeable by water, air, etc.
- Synonyms:
- riddled, sievelike, pervious, penetrable
adjective
-
permeable to water, air, or other fluids
-
biology geology having pores; poriferous
-
easy to cross or penetrate
the porous border into Thailand
the most porous defence in the league
Other Word Forms
Etymology
Origin of porous
First recorded in 1350–1400; Middle English, variant of porose, from Medieval Latin porōsus; see pore 2, -ous
Explanation
If something is full of tiny holes or openings, you can describe it as porous. A sponge is porous, and if the border between countries is open for anyone to cross easily, it too can be called porous. You can see the word pore — meaning "a tiny opening" — in porous. When potters make a mug, they use special glazes to seal the porous clay, which otherwise would absorb the liquid you put in the mug. This meaning has expanded so porous can describe any barrier that allows easy passage in and out, like the porous border between two countries that allows residents to move easily between them.
Vocabulary lists containing porous
Can You Dig It? Words for Dirt and Soil
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
"An Awful Human Trade," Vocabulary from the news article
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
All Thirteen
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
U.S. officials say Syria could play a larger role in securing its porous border with Lebanon.
From The Wall Street Journal ● Jul. 21, 2026
There were outdoor hallways, planted patios, a sculpted and porous internal courtyard, and even a new “paseo” next door — a closed street turned into a lovely space for farmers markets and other gatherings.
From Los Angeles Times ● Jun. 18, 2026
Congolese mining towns tend to be porous and migrant-heavy, rough, difficult places to live in some of the country’s roughest, most difficult areas, where there is plenty of reason to distrust outsiders.
From Slate ● Jun. 9, 2026
In those experiments, sodium chloride crystals form in a loose, porous structure as water evaporates.
From Science Daily ● May 31, 2026
Slag looks like pieces of porous rock but actually is the cinders left over when iron ore is melted down to make steel.
From "Flying to the Moon: An Astronaut's Story" by Michael Collins
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
