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 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, Journal Sentinel, 25 Apr. 2024
In places where molten rock sizzles close to the surface, water will seep through porous volcanic rock, warm up and bubble upward as hot water, steam or both.
—Katarina Zimmer, Smithsonian Magazine, 22 Apr. 2024
See all Example Sentences for porous 
Laura Schulte, Journal Sentinel, 25 Apr. 2024
In places where molten rock sizzles close to the surface, water will seep through porous volcanic rock, warm up and bubble upward as hot water, steam or both.
—Katarina Zimmer, Smithsonian Magazine, 22 Apr. 2024
See all Example Sentences for porous
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'porous.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Dictionary Entries Near porous
Cite this Entry
“Porous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/porous. Accessed 3 May. 2024.
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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