porosity

IPA/pɔːˈrɒsəti/
IPA/pɔːˈrɑːsəti/

porosity — noun

1. the degree to which a material contains tiny holes or spaces inside it, allowing

1.nounB2
Definition

the degree to which a material contains tiny holes or spaces inside it, allowing liquids or gases to pass through slowly

Example

The high porosity of the sandstone allowed water to seep through quickly.

collocation: high porosity / low porosity

Roya tested the porosity of the clay before using it for her pottery project.

test the porosity of [material]

Common collocations
  • high porosity
  • low porosity
  • soil porosity
  • rock porosity
  • hair porosity
  • increase porosity
  • reduce porosity
  • test the porosity of
Synonyms
  • permeability

    focuses on how easily fluids pass through, whereas porosity emphasises the void spaces themselves

  • absorbency

    describes the ability to take in liquid, which is related to but not the same as porosity

  • sponginess

    more informal; describes the physical feel of being soft and full of holes

Antonyms
  • density

    a material with high density typically has low porosity

  • solidity

    the state of being solid and without internal spaces

Grammar Patterns

uncountable: Porosity [verb] ...

countable in technical contexts: ... porosities ...

Usage Note

Typically uncountable. In technical or comparative contexts, the plural form 'porosities' can refer to different degrees or types of porosity across materials.

Common Mistakes

The porosity of this sponge is very porous.
The porosity of this sponge is very high.
'porous' is an adjective describing the material itself; use 'high' or 'low' to describe the degree of porosity.
This material has many porosities.
This material has high porosity.
In everyday use, 'porosity' is uncountable; the plural form is reserved for technical comparisons.

Word family

  • porous
    adjectiveB2
  • pore
    nounB2
  • porously
    adverbC2
  • nonporous
    adjectiveC1

Synonym discussion

Sense: noun/1

Porosity, permeability, absorbency, and density describe related but distinct material properties. Porosity refers to the amount of empty space (pores) inside a material — for example, how much air a sponge holds. Permeability describes how easily a fluid can flow through those connected pores; a material can be porous but not permeable if the pores are isolated. Absorbency is the practical ability to take in liquid, which depends on both porosity and the material's chemical attraction to the liquid. Density is essentially the opposite: a dense material has little empty space and therefore low porosity. In everyday contexts, people talk about hair porosity to choose the right hair products, or soil porosity to judge how well water drains in a garden.

porosity ↗permeability ↗absorbency ↗density ↗

Etymology

GreekLatinEnglish

Porosity comes from medieval Latin 'porositas', which is built on Latin 'porus' meaning 'pore' or 'small opening'. The Latin word was borrowed from Greek 'poros', meaning 'passage' or 'channel'. The word entered English in the late 14th century, first used in medical and then in scientific contexts to describe the quality of having tiny openings.

First known use

14th century

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