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 porous border has long been a conduit for the smuggling of people, weapons, and drugs.
—
Kareem Chehayeb and Abby Sewell, The Christian Science Monitor, 8 Feb. 2025
Mark Hall, an investment banker who has been traveling to the Dominican Republic for 35 years, is hoping that Rubio’s visit will prove positive for a project he’s been involved in: the installation of smart technology along the two countries’ porous border.
—Jacqueline Charles, Miami Herald, 6 Feb. 2025
The best way to shorten that decay time is to fill the room with as much soft, porous mass as possible.
—Parker Hall, WIRED, 30 Jan. 2025
From declaring an emergency on the porous southern border to ending former President Joe Biden’s restrictions on energy production, most of the orders reflect things that need to be done to restore order and prosperity.
—Nolan Finley, The Mercury News, 28 Jan. 2025
See all Example Sentences for porous 
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Kareem Chehayeb and Abby Sewell, The Christian Science Monitor, 8 Feb. 2025
Mark Hall, an investment banker who has been traveling to the Dominican Republic for 35 years, is hoping that Rubio’s visit will prove positive for a project he’s been involved in: the installation of smart technology along the two countries’ porous border.
—Jacqueline Charles, Miami Herald, 6 Feb. 2025
The best way to shorten that decay time is to fill the room with as much soft, porous mass as possible.
—Parker Hall, WIRED, 30 Jan. 2025
From declaring an emergency on the porous southern border to ending former President Joe Biden’s restrictions on energy production, most of the orders reflect things that need to be done to restore order and prosperity.
—Nolan Finley, The Mercury News, 28 Jan. 2025
See all Example Sentences for porous
Dictionary Entries Near porous
Cite this Entry
“Porous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/porous. Accessed 18 Feb. 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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