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
At Congonhas Airport, the most notable change was the resurfacing of the runway, now with transverse grooving and a porous friction layer to improve water drainage and reduce the risk of skidding.
—
Isadora Wandermurem, Time, 23 Apr. 2025
With the rise of remote work, smartphones and constant connectivity, the boundaries between these roles have become increasingly porous.
—Mark Travers, Forbes.com, 21 Apr. 2025
Rain falling in the Everglades percolates through the porous limestone and recharges the Biscayne Aquifer, which supplies drinking water for 1 in 3 Floridians.
—John Kominoski, The Conversation, 15 Apr. 2025
The brains of people with dementia had more, though the researchers noted that might be because those brains have a more porous blood-brain barrier and are less able to clear toxins.
—Nina Agrawal, New York Times, 8 Apr. 2025
See All Example Sentences for porous
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Isadora Wandermurem, Time, 23 Apr. 2025
With the rise of remote work, smartphones and constant connectivity, the boundaries between these roles have become increasingly porous.
—Mark Travers, Forbes.com, 21 Apr. 2025
Rain falling in the Everglades percolates through the porous limestone and recharges the Biscayne Aquifer, which supplies drinking water for 1 in 3 Floridians.
—John Kominoski, The Conversation, 15 Apr. 2025
The brains of people with dementia had more, though the researchers noted that might be because those brains have a more porous blood-brain barrier and are less able to clear toxins.
—Nina Agrawal, New York Times, 8 Apr. 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 2 May. 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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