porous

American  

[pawr-uhs, pohr-] / ˈpɔr əs, ˈpoʊr- /

adjective

1. full of pores.

2. permeable by water, air, etc.

   Synonyms:

   riddled, sievelike, pervious, penetrable

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porous British  

/ ˈpɔːrəs /

adjective

1. permeable to water, air, or other fluids

2. biology geology having pores; poriferous

3. easy to cross or penetrate

   the porous border into Thailand

   the most porous defence in the league

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porous Scientific  

/ pôr′əs /

1. Having many pores or other small spaces that can hold a gas or liquid or allow it to pass through.

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Other Word Forms

Derived Forms

• unporous
  adjective
• nonporousness
  noun
• unporousness
  noun
• porously
  adverb
• nonporous
  adjective
• porousness
  noun

Etymology

Origin of porous

First recorded in 1350–1400; Middle English, variant of porose, from Medieval Latin porōsus; see pore ², -ous

Explanation

If something is full of tiny holes or openings, you can describe it as porous. A sponge is porous, and if the border between countries is open for anyone to cross easily, it too can be called porous. You can see the word pore — meaning "a tiny opening" — in porous. When potters make a mug, they use special glazes to seal the porous clay, which otherwise would absorb the liquid you put in the mug. This meaning has expanded so porous can describe any barrier that allows easy passage in and out, like the porous border between two countries that allows residents to move easily between them.

Example Sentences

The paper, "A Study on Welding of Porous Metals and Metallic Foams," is published in the journal Advanced Engineering Materials.

From Science Daily • Dec. 14, 2023

Porous defense has allowed league’s sixth-highest goals-against total, underscoring a problem many had assumed fixed last season.

From Seattle Times • Nov. 10, 2023

Porous and agile; simmering beneath and around the voices; and only occasionally, briefly exploding, this is music as a vehicle for exploring and intensifying drama.

From New York Times • Jul. 7, 2021

Porous materials, such as wood, aren’t the best choice for spots that see a lot of humidity or rain, and painted pieces won’t last in sunny locations, where the paint can peel or crack.

From Washington Post • Apr. 27, 2021

Porous charcoal, best made from such dense wood as coconut shells, was packed in the respirator box together with layers of such chemicals as will catch the gases to be expected.

From Creative Chemistry Descriptive of Recent Achievements in the Chemical Industries by Slosson, Edwin E.