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

Each mug is made from non-reactive, non-porous porcelain enamel that resists stains, rust, and scratches, so the set will stand the test of time. —Stephanie Osmanski, Better Homes & Gardens, 30 Nov. 2025

But the Ravens lost by 18 points and were able to muster just 14 points against a Cincinnati defense that has been extremely porous. —Robert Marvi, MSNBC Newsweek, 29 Nov. 2025

These options are porous, effective, and pose fewer long-term environmental threats if lost, unlike their plastic counterparts. —Kara Fox, CNN Money, 29 Nov. 2025

Choose a porous pot like terracotta that lets moisture evaporate and prevents any excess moisture from causing problems. —Karen Brewer Grossman, Southern Living, 28 Nov. 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