ˌpərmēəˈbiləd.ē, ˌpə̄m-, ˌpəim-, -lətē, -i noun
1. : the quality or state of being permeable
the permeability of protective films
the permeability of a membrane
the water vapor permeability of leather is inherently high — Technical News Bulletin
2. : the property of a porous material that is measured by the rate by volume at which a fluid of unit viscosity passes through unit cross section of the material under unit pressure gradient ; specifically : a measure of the ease of fluid flow through rocks — compare darcy , darcy's law
3. : the measure of the rate of diffusion of gas through intact balloon fabric usually expressed in liters per square meter of fabric per 24 hours under standard conditions
4. : the property of a magnetizable substance that determines the degree in which it modifies the magnetic flux in the region occupied by it in a magnetic field ; specifically : the ratio of the induction to the magnetizing force in the substance