porous

adjective

po·​rous ˈpȯr-əs 

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

Synonyms

• penetrable
• permeable

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

Secrets, Bohr said, are porous where nature is concerned. —MSNBC Newsweek, 8 Oct. 2025

Kitagawa began to research the potential for creating porous molecular structures, presenting his first one in 1992. —Katie Hunt, CNN Money, 8 Oct. 2025

Susumu Kitagawa, Richard Robson, and Omar Yaghi discovered that copper ions could be used to create a crystal with large cavities within it, which was porous to smaller atoms and molecules but blocked larger ones. —Tom Chivers, semafor.com, 8 Oct. 2025

Enter Dowdle, who shredded the Dolphins’ porous run D on the way to 206 yards, four shy of DeAngelo Williams’ team record. —Joseph Person, New York Times, 7 Oct. 2025

Word History

First Known Use

14th century, in the meaning defined at sense 1a

Phrases Containing porous

• diffuse-porous
• ring-porous

Rhymes for porous

• chloris
• chorus
• horus
• lores
• morrice
• morus
• orris
• porus
• torus
• authorise
• clitoris
• liquorice

Kids 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