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
Derived 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
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"An Awful Human Trade," Vocabulary from the news article
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All Thirteen
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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.
India shares a long and porous border with Bangladesh, where migration has historically been driven by economic hardship and longstanding family links.
From Barron's • May 29, 2026
As that happens, the porous rock temporarily locks up, slowing or stopping the rupture before it can continue spreading and becoming larger.
From Science Daily • May 16, 2026
Numbers were once even greater - after a devastating famine in the mid-1990s triggered what rights groups described as a silent exodus over a more porous border with China.
From BBC • Mar. 27, 2026
They’re porous defensively and have a boring, predictable offense largely consisting of alternating one-on-one isolations between their “Big Three” most every trip down the court.
From Los Angeles Times • Feb. 28, 2026
The border between their lands was porous; the Queen’s death would hover over their cities and villages, too.
From "Huntress" by Malinda Lo
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.
