permeability
pur-mee-uh-BIL-i-tee
/ˌpɜːrmiəˈbɪlɪti/
The state or quality of allowing liquids or gases to pass through.
In packaging, it refers to the rate at which gases (like oxygen, carbon dioxide, or water vapor) diffuse through a plastic film or barrier material.
The story behind the word. The root 'meare' is an ancient Indo-European root meaning to go or exchange. Combined with 'per-', it gave Latin the verb 'permeare', describing how water seeps through soil or how air moves through fabric. It entered English scientific writing in the 18th century.
Word relationships
- porosity: Porosity refers to the presence of physical pores or voids in a material, whereas permeability is the measure of how easily fluids can flow through those pores or diffuse at a molecular level.
- penetrability: Penetrability is a general term for being able to be pierced or entered, while permeability is a specific scientific rate of flow.
- impermeability: The state of being completely impassable to fluids or gases.
- resistance: In materials science, resistance is the ability to oppose the flow or passage of substances.
Commonly confused with
- absorption: Absorption is the process of taking a substance into the bulk of a material, while permeability is the passage of a substance completely through a material.
Word family
- permeable (adjective): Allowing liquids or gases to pass through.
- permeate (verb): To spread or pass through every part of.
Collocations
- oxygen permeability
- gas permeability
- water vapor permeability
- low permeability
Example sentences
- "The permeability of the plastic film to oxygen determines the shelf life of the product, as high gas transmission rates lead to rapid oxidation." Polymer science journal
Memory hook
Think of a 'permanent' stream that 'permeates' through the rocks because of their high 'permeability'. Permeability lets things pass, like water vapor or a gas.
When not to use
Do not use to describe physical holes or tears; it refers to molecular-level diffusion through solid-looking materials.
Fun facts
- Plastic bottles of soda lose their carbonation over time because plastic has a natural permeability to carbon dioxide, allowing the gas to slowly escape through the bottle walls.
Related words
Explore more words
permeable, aquifer, leach, transparent, conductivity, translucent
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