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
It’s engineered for cooling, using silica particles and a porous structure to scatter sunlight and prevent heating.
—
Rupendra Brahambhatt, Interesting Engineering, 3 May 2026
Harsh chemicals are prone to damaging grout over time, which can lead to issues like grout becoming porous and then collecting toxic fumes from cleaners that are then released back into the air.
—Ashlyn Needham, Southern Living, 2 May 2026
The risk of insecurity spreading across West Africa’s porous borders, even affecting stable democracies such as Senegal and Ghana, is real.
—Ulf Laessing, semafor.com, 30 Apr. 2026
Rather than replacing the island’s aging pipe system, the approach would largely rely on the existing drainage network to collect rainwater and funnel it into wells, where it would be injected below the surface into porous rock formations.
—Ashley Miznazi, Miami Herald, 28 Apr. 2026
See All Example Sentences for porous
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Rupendra Brahambhatt, Interesting Engineering, 3 May 2026
Harsh chemicals are prone to damaging grout over time, which can lead to issues like grout becoming porous and then collecting toxic fumes from cleaners that are then released back into the air.
—Ashlyn Needham, Southern Living, 2 May 2026
The risk of insecurity spreading across West Africa’s porous borders, even affecting stable democracies such as Senegal and Ghana, is real.
—Ulf Laessing, semafor.com, 30 Apr. 2026
Rather than replacing the island’s aging pipe system, the approach would largely rely on the existing drainage network to collect rainwater and funnel it into wells, where it would be injected below the surface into porous rock formations.
—Ashley Miznazi, Miami Herald, 28 Apr. 2026
See All Example Sentences for porous
Cite this Entry
“Porous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/porous. Accessed 4 May. 2026.
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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