permeability

American  

[pur-mee-uh-bil-i-tee] / ˌpɜr mi əˈbɪl ɪ ti /

noun

1. the property or state of being permeable.

2. Also called magnetic permeability.  Electricity. a measure of the change in magnetic induction produced when a magnetic material replaces air, expressed as a coefficient or a set of coefficients that multiply the components of magnetic intensity to give the components of magnetic induction.

3. Geology. the capability of a porous rock or sediment to permit the flow of fluids through its pore spaces.

4. Aeronautics. the rate at which gas is lost through the envelope of an aerostat, usually expressed as the number of liters thus diffused in one day through a square meter.

5. Nautical. the capacity of a space in a vessel to absorb water, measured with reference to its temporary or permanent contents and expressed as a percentage of the total volume of the space.

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permeability British  

/ ˌpɜːmɪəˈbɪlɪtɪ /

noun

1. the state or quality of being permeable

2.  μ.  a measure of the response of a medium to a magnetic field, expressed as the ratio of the magnetic flux density in the medium to the field strength; measured in henries per metre See also relative permeability magnetic constant

3. civil engineering the rate of diffusion of a fluid under pressure through soil

4. the rate at which gas diffuses through the surface of a balloon or airship, usually expressed in litres per square metre per day

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permeability Scientific  

/ pûr′mē-ə-bĭl′ĭ-tē /

1. The ability of a substance to allow another substance to pass through it, especially the ability of a porous rock, sediment, or soil to transmit fluid through pores and cracks. Geologic permeability is usually measured in millidarcies.

2. See more at darcy

3. Magnetic permeability.

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Usage

What does permeability mean? Permeability is the quality or state of being permeable—able to be penetrated or passed through, especially by a liquid or gas. The verb permeate means to penetrate, pass through, and often become widespread throughout something. Similar words are pervade and saturate. Permeate can be used both in the context of the physical spread of something within a space and in more figurative ways. Water permeates the soil. Dye permeates fabric. An idea can permeate someone’s mind. In these cases, the fabric and the mind could be described as permeable. Things that are permeable have different levels of permeability. For example, certain materials may easily absorb liquid, while others may only allow small amounts of liquid to permeate their surface. The word permeability is used in several more specific ways in the context of ships, aircraft, electricity, and geology. Example: This type of stone was chosen for its permeability—it absorbs water.

Other Word Forms

• nonpermeability noun

Etymology

Origin of permeability

First recorded in 1750–60; perme(able) + -ability ( def. )

Explanation

Use the noun permeability to describe how slowly or quickly water soaks into something, particularly soil. You're most likely to come across the word permeability in an earth science class. The permeability of something means basically the same thing as how absorbent it is — for example, a gravel driveway has much greater permeability than a heavy clay soil does. The root word is the Latin permeabilis, "that can be passed through."

Example Sentences

Other doors were sealed, it added, "to prevent excessive permeability of the historic building's spaces - structures dating back to the 1500s - considering their changed functions and the evolving international context".

From BBC • Apr. 3, 2026

“Fractures, fluid, pathways, permeability, that’s kind of the name of the game for us,” said Nils Caliandro, the lead geologist for Big Blind.

From The Wall Street Journal • Jan. 21, 2026

In celiac disease, there's debate about the early stages of increased permeability.

From Science Daily • May 16, 2024

During heavy exercise, the stomach produces less acid than usual and gut permeability increases, meaning that small molecules in your gut are more likely to escape across the membrane into your blood.

From Salon • May 9, 2024

The permeability of North Korea’s border tends to improve when border guards and local officials can accept bribes without draconian punishment from higher-ups.

From "Escape from Camp 14: One Man's Remarkable Odyssey from North Korea to Freedom in the West" by Blaine Harden