1
a
: possessing or full of pores
b
: containing vessels
hardwood is porous
2
a
: permeable to fluids
b
: permeable to outside influences
3
: capable of being penetrated
porous national boundaries
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
The porous polymer coating that reflects up to 97 percent of sunlight and radiates heat into the air, keeping surfaces up to six degrees cooler than the surrounding air even under direct sun.
—
Prabhat Ranjan Mishra, Interesting Engineering, 9 Nov. 2025
That should allow Goff plenty of opportunities to make downfield plays against Washington's porous pass defense.
—Jacob Camenker, USA Today, 9 Nov. 2025
Yet the show, and the echo between these two men, hints at an interesting idea that the line between madness and ideology is actually porous.
—Nicholas Quah, Vulture, 7 Nov. 2025
While the Buffalo secondary deserves a hat tip, the Chiefs’ offensive line — which had been good enough coming into the game — was porous (and injured) at times, leaving Mahomes vulnerable to take on some nasty hits.
—Kansas City Star, 3 Nov. 2025
See All Example Sentences for porous
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Prabhat Ranjan Mishra, Interesting Engineering, 9 Nov. 2025
That should allow Goff plenty of opportunities to make downfield plays against Washington's porous pass defense.
—Jacob Camenker, USA Today, 9 Nov. 2025
Yet the show, and the echo between these two men, hints at an interesting idea that the line between madness and ideology is actually porous.
—Nicholas Quah, Vulture, 7 Nov. 2025
While the Buffalo secondary deserves a hat tip, the Chiefs’ offensive line — which had been good enough coming into the game — was porous (and injured) at times, leaving Mahomes vulnerable to take on some nasty hits.
—Kansas City Star, 3 Nov. 2025
See All Example Sentences for porous
Cite this Entry
“Porous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/porous. Accessed 14 Nov. 2025.
Copy CitationKids Definition
porous
adjective
po·rous
ˈpōr-əs 
ˈpȯr-
1
: full of pores
2
: capable of absorbing liquids
Medical Definition
porous
adjective
po·rous
ˈpōr-əs, ˈpȯr-
1
: possessing or full of pores
porous bones
2
: permeable to fluids
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