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 of porous

• 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

The team explored how diaphragms, which are inexpensive and robust porous separators, could handle the demanding conditions of carbon dioxide conversion. —Aamir Khollam, Interesting Engineering, 5 Nov. 2025

While the Buffalo secondary deserves a hat tip, the Chiefs’ offensive line — which had been good enough coming into the game — was porous (and injured) at times, leaving Mahomes vulnerable to take on some nasty hits. —Kansas City Star, 3 Nov. 2025

Every glimpse of change or hope was followed by the same porous, intrinsic habits Florida has shown all season. —Noah White, Miami Herald, 2 Nov. 2025

The defence remains porous, error-prone and vulnerable on corners. —Chris Weatherspoon, New York Times, 31 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