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
Do not soak or submerge, as wood is porous.
—
Caroline Lubinsky, Martha Stewart, 17 May 2026
Having been filtered through porous underground lava for decades, Silfra boasts exceptionally pure drinking water.
—Carinne Geil Botta, Travel + Leisure, 16 May 2026
The new report describes a sprawling transnational criminal system in which Brazilian syndicates, Colombian guerrilla dissidents, Ecuadorian gangs and local crime families collaborate and compete simultaneously while moving drugs, gold, weapons and money across porous borders.
—Antonio María Delgado, Miami Herald, 13 May 2026
Horticultural fleece, blankets, cardboard boxes, and other porous materials can be used to trap ground heat around plants.
—Kim Toscano, Southern Living, 13 May 2026
See All Example Sentences for porous
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Caroline Lubinsky, Martha Stewart, 17 May 2026
Having been filtered through porous underground lava for decades, Silfra boasts exceptionally pure drinking water.
—Carinne Geil Botta, Travel + Leisure, 16 May 2026
The new report describes a sprawling transnational criminal system in which Brazilian syndicates, Colombian guerrilla dissidents, Ecuadorian gangs and local crime families collaborate and compete simultaneously while moving drugs, gold, weapons and money across porous borders.
—Antonio María Delgado, Miami Herald, 13 May 2026
Horticultural fleece, blankets, cardboard boxes, and other porous materials can be used to trap ground heat around plants.
—Kim Toscano, Southern Living, 13 May 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 18 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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