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
One of the main reasons for the vast difference is that toilets are made of non-porous material, whereas sponges are highly porous and inviting for germs.
—
Mary Cornetta, Better Homes & Gardens, 24 Sep. 2025
There is no need to use bleach, soap or a produce wash — fruits and vegetables are porous and can absorb the chemicals.
—Sandee Lamotte, CNN Money, 24 Sep. 2025
The state could look at banning the application of fertilizer or manure in areas of the state where the groundwater is close to the surface, or porous rock makes the groundwater ripe for contamination, advocates have suggested.
—Laura Schulte, jsonline.com, 22 Sep. 2025
The tannins in coffee are very good at penetrating porous ceramic (as well as our teeth) and leaving behind ugly brown stains.
—Brandee Gruener, Southern Living, 20 Sep. 2025
See All Example Sentences for porous
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Mary Cornetta, Better Homes & Gardens, 24 Sep. 2025
There is no need to use bleach, soap or a produce wash — fruits and vegetables are porous and can absorb the chemicals.
—Sandee Lamotte, CNN Money, 24 Sep. 2025
The state could look at banning the application of fertilizer or manure in areas of the state where the groundwater is close to the surface, or porous rock makes the groundwater ripe for contamination, advocates have suggested.
—Laura Schulte, jsonline.com, 22 Sep. 2025
The tannins in coffee are very good at penetrating porous ceramic (as well as our teeth) and leaving behind ugly brown stains.
—Brandee Gruener, Southern Living, 20 Sep. 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 26 Sep. 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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