What does permeability mean?
Permeability is the degree to which a material allows a fluid, gas, or other substance to pass through it. In biology, it commonly describes the ability of a membrane to permit selected substances to cross; in geology and construction, it can refer to how readily water or air moves through soil, concrete, or another material. The term also has a figurative use for the ease with which ideas, people, or information pass through organizational or social boundaries. Related physical properties include porosity, which measures the spaces within a material, and permeability, which measures how readily fluids can move through those spaces. Although the word can sound technical, it is useful for describing anything characterized by openness, passage, or the ability to penetrate a barrier.
nounThe degree to which a material allows a fluid, gas, or other substance to pass through it. It is also used figuratively for the ease with which people, information, or ideas can pass through boundaries or systems.
- The physical property of allowing substances to pass through a material.
- The ease with which something can move through or penetrate a system, organization, or boundary.
- The property of a material or magnetic field that determines how readily it allows magnetic flux to pass through it.
"The membrane's permeability allows small molecules to pass through while retaining larger proteins."
"Engineers tested the soil's permeability before deciding whether the site could support a drainage system."
"The policy increased the permeability of the organization by allowing more employees to share information."
The plural is used when comparing the permeability of different materials or referring to several measurable permeability values.
"The researchers compared the permeabilities of the two polymer films."
Permeability is the reason a raincoat keeps out a downpour while allowing the faintest breeze to pass through.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does permeability come from?
Permeability was formed in the early 19th century from the Latin permeare, meaning “to pass through,” combined with the suffix -ability. Permeare developed from per-, meaning “through,” and meare, a form of Latin migrare, meaning “to move.” English borrowed related forms including permeate, permeable, and permeation, while other cognates include permutation and the rarer permeance.
Related word forms
How permeability is actually used
In technical contexts, particularly physics, biology, and materials science, permeability is usually used as a measurable quantitative property. Outside those fields, it often has the figurative sense of openness or ease of movement. The distinction from porosity is that permeability describes the ease with which a fluid passes through, whereas porosity describes the amount of space within a material.