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
That distinction matters for planetary defense, scientists say, because a fragile, porous asteroid would react to a spacecraft's impact very differently than a dense, solid one.
—
Sharmila Kuthunur, Space.com, 13 Oct. 2025
The main difference between ceramic and terra cotta is that ceramic barrels are kiln fired, offering a smooth, non-porous surface that minimizes interaction with the atmosphere as well as with the clay itself.
—Mike Desimone, Robb Report, 12 Oct. 2025
This process transformed the plastic into porous carbon powder, which was then combined with carbon black and a polymer binder to form thin electrode layers.
—Neetika Walter, Interesting Engineering, 9 Oct. 2025
It was first reported by Gérard Férey, one of the foundational figures in the MOF and porous framework community who sadly died in 2017.
—Stavroula Alina Kampouri, The Conversation, 9 Oct. 2025
See All Example Sentences for porous
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Sharmila Kuthunur, Space.com, 13 Oct. 2025
The main difference between ceramic and terra cotta is that ceramic barrels are kiln fired, offering a smooth, non-porous surface that minimizes interaction with the atmosphere as well as with the clay itself.
—Mike Desimone, Robb Report, 12 Oct. 2025
This process transformed the plastic into porous carbon powder, which was then combined with carbon black and a polymer binder to form thin electrode layers.
—Neetika Walter, Interesting Engineering, 9 Oct. 2025
It was first reported by Gérard Férey, one of the foundational figures in the MOF and porous framework community who sadly died in 2017.
—Stavroula Alina Kampouri, The Conversation, 9 Oct. 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 16 Oct. 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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