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 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
Michigan also capitalized on the Terps’ porous defense in the lane.
—Edward Lee, Baltimore Sun, 15 Mar. 2025
West Ham were porous defensively, struggling with forming an identity and a lot of fans were ready for change.
—Roshane Thomas, The Athletic, 14 Mar. 2025
These materials are non-porous, which means the bleach won't damage them, and can handle the brightening and cleaning agents of the solution.
—Ashlyn Needham, Southern Living, 15 Mar. 2025
See All Example Sentences for porous
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Nina Agrawal, New York Times, 8 Apr. 2025
Michigan also capitalized on the Terps’ porous defense in the lane.
—Edward Lee, Baltimore Sun, 15 Mar. 2025
West Ham were porous defensively, struggling with forming an identity and a lot of fans were ready for change.
—Roshane Thomas, The Athletic, 14 Mar. 2025
These materials are non-porous, which means the bleach won't damage them, and can handle the brightening and cleaning agents of the solution.
—Ashlyn Needham, Southern Living, 15 Mar. 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 19 Apr. 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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