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

Blasted from porous lava rock, the canals have to be completely full for gravity to push water across the district’s more than 42,000 acres. — Emily Cureton Cook, ProPublica, 26 June 2026

Major organs start to shut down – the barriers that separate the gut from the rest of the intestines can become more porous, leaking deadly toxins into the bloodstream and the heart fails. — Taylor Ward, CNN Money, 24 June 2026

The second means larger casks over small new oak, and porous concrete, whose micro-oxygenation builds texture without leaving a flavour of its own. — Paul Caputo, Forbes.com, 23 June 2026

Astilbe also has an extensive root system that keeps the soil more porous—a win for hydrangeas, which don't like wet feet. — Madeline Buiano, Martha Stewart, 22 June 2026

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