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 walls are likely becoming porous through behavior rather than policy — which is how convergence always happens, quietly and from below, until someone in leadership notices and calls it a breach.
—
Vibhas Ratanjee, Forbes.com, 14 June 2026
Stone surfaces, including marble, granite, and quartz, are porous and bleach can wreak havoc of these beautiful materials.
—Lauren David, Southern Living, 12 June 2026
Combined with the country’s porous land border with the Dominican Republic, the deteriorating conditions have helped transform Haiti into a regional transit hub for drug trafficking, the report found.
—Jacqueline Charles, Miami Herald, 10 June 2026
Queen City Boundaries between urban and rural America were always porous.
—Matthew Smith, The Conversation, 8 June 2026
See All Example Sentences for porous
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Vibhas Ratanjee, Forbes.com, 14 June 2026
Stone surfaces, including marble, granite, and quartz, are porous and bleach can wreak havoc of these beautiful materials.
—Lauren David, Southern Living, 12 June 2026
Combined with the country’s porous land border with the Dominican Republic, the deteriorating conditions have helped transform Haiti into a regional transit hub for drug trafficking, the report found.
—Jacqueline Charles, Miami Herald, 10 June 2026
Queen City Boundaries between urban and rural America were always porous.
—Matthew Smith, The Conversation, 8 June 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 16 Jun. 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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