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.

Origin of permeability

1750–60; permea(ble) + -bility
Related formsnon·per·me·a·bil·i·ty, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for permeability

Contemporary Examples of permeability

Historical Examples of permeability

British Dictionary definitions for permeability


  1. the state or quality of being permeable
  2. 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 metreSymbol: μ 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
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for permeability

1733, from permeable + -ity, or else from French perméabilité.

Online Etymology Dictionary, © 2010 Douglas Harper

permeability in Medicine


  1. The property or condition of being permeable.
  2. The rate of flow of a liquid or gas through a porous material.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

permeability in Science


  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. See more at darcy.
  2. Magnetic permeability.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.