porosity

American  

[paw-ros-i-tee, poh-, puh-] / pɔˈrɒs ɪ ti, poʊ-, pə- /

noun

plural

porosities

1. the state or quality of being porous.

2. Geology, Engineering. the ratio, expressed as a percentage, of the volume of the pores or interstices of a substance, as a rock or rock stratum, to the total volume of the mass.

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porosity British  

/ pɔːˈrɒsɪtɪ /

noun

1. the state or condition of being porous

2. geology the ratio of the volume of space to the total volume of a rock

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porosity Scientific  

/ pə-rŏs′ĭ-tē,pô- /

1. The condition of being porous.

2. The ratio of the volume of all the pores in a material to the volume of the whole.

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Etymology

Origin of porosity

First recorded in 1350–1400; Middle English porosytee, from Medieval Latin porōsitās ; see origin at porous, -ity

Explanation

Porosity is the quality of being porous, or full of tiny holes. Liquids go right through things that have porosity. Go back far enough and you’ll find that porosity stems from the Greek word poros for "pore," which means “passage.” So something with porosity lets things through. Most pants have porosity, as you unfortunately notice when you spill soup on them — the soup goes right through. On the other hand, a raincoat has no porosity because it's waterproof. If your roof is leaking during the rain, it has some porosity, which is a problem. You can remember porosity by imagining liquids pouring through things.

Example Sentences

"Porosity is often ignored because it's difficult to include in models, but our simulations show it can strongly affect the impact process and shape of craters left behind."

From Science Daily • Mar. 17, 2026

Porosity is known to affect the structural integrity of mollusk shells, making shells weaker and potentially more susceptible to damage.

From Science Daily • Apr. 17, 2024

Porosity is a description of how much space there could be to hold water under the ground, and permeability describes how those pores are shaped and interconnected.

From Textbooks • Jan. 1, 2015

Porosity is expressed as a percentage calculated from the volume of open space in a rock compared with the total volume of rock.

From Textbooks • Jan. 1, 2015

Porosity: the state of having small openings or passages between the particles of matter.

From Agriculture for Beginners Revised Edition by Burkett, Charles William