Permeability, permeable, and semipermeable may refer to:

Chemistry

Drug permeability In medicinal chemistry, Drug Permeability is an empirical parameter that indicates how quickly a chemical entity or an active pharmaceutical ingredient crosses a biological membrane or another biological barrier to become bioavailable in the body. ...

Semipermeable membrane Semipermeable membrane is a type of synthetic or biologic, polymeric membrane that allows certain molecules or ions to pass through it by osmosis. The rate of passage depends on the pressure, concentration, and temperature of the molecules o ...

, a membrane which will allow certain molecules or ions to pass through it by diffusion *

Vascular permeability Vascular permeability, often in the form of capillary permeability or microvascular permeability, characterizes the permeability of a blood vessel wall–in other words, the blood vessel wall's capacity to allow for the flow of small molecules ( ...

, the movement of fluids and molecules between the vascular and extravascular compartments *

Permeation In physics and engineering, permeation (also called imbuing) is the penetration of a wikt:permeate#English, permeate (a fluid such as a liquid, gas, or vapor) through a solid. It is directly related to the concentration gradient of the permeate, ...

of a gas or vapor through a solid substance

Earth and soil science

Permeability (earth sciences) In fluid mechanics, materials science and Earth sciences, the permeability of porous media (often, a rock or soil) is a measure of the ability for fluids (gas or liquid) to flow through the media; it is commonly symbolized as ''k''. Fluids c ...

, a measure of the ability of a material (such as rocks) to transmit fluids **

Relative permeability In multiphase flow in porous media, the relative permeability of a Phase (matter), phase is a dimensionless measure of the effective Permeability (Earth sciences), permeability of that phase. It is the ratio of the effective permeability of that ...

, in multiphase flow in porous media *

Permeability (foundry sand) Permeability is a property of foundry sand with respect to how well the sand can vent, ''i.e.'' how well gases pass through the sand. And in other words, permeability is the property by which we can know the ability of material to transmit fluid/ ...

, a test of the venting characteristics of a rammed foundry sand *

Hydraulic conductivity In science and engineering, hydraulic conductivity (, in SI units of meters per second), is a property of porous materials, soils and Rock (geology), rocks, that describes the ease with which a fluid (usually water) can move through the porosity, ...

, the permeability of soil for water

Electromagnetism

Permeability (electromagnetism) In electromagnetism, permeability is the measure of magnetization produced in a material in response to an applied magnetic field. Permeability is typically represented by the (italicized) Greek letter Mu (letter), ''μ''. It is the ratio of t ...

, the degree of magnetization of a material in response to a magnetic field **

Vacuum permeability The vacuum magnetic permeability (variously ''vacuum permeability'', ''permeability of free space'', ''permeability of vacuum'', ''magnetic constant'') is the magnetic permeability in a classical vacuum. It is a physical constant, conventionally ...

, permeability of free space or magnetic constant, a physical constant, the value of magnetic permeability in a classical vacuum

Vehicles and transport

Permeability (nautical) {{short description, Percentage of empty volume in a ship Permeability of a space in a ship is the percentage of empty volume in that space. Permeability is used in ship survivability and damaged stability calculations in ship design. In this case ...

, in ship design, the percentage of empty space in a compartment or tank *

Permeability (spatial and transport planning) In urban design, permeability and connectivity are terms that describe the extent to which urban forms permit (or restrict) movement of people or vehicles in different directions. The terms are often used interchangeably, although differentiated ...

, the extent to which the layout of urban forms enables people or vehicles to move in different directions

Other uses

Air permeability Textile fibers, threads, yarns and fabrics are measured in a multiplicity of units. * A fiber, a single filament of natural material, such as cotton, linen or wool, or artificial material such as nylon, polyester, metal or mineral fiber, or huma ...

, characteristic of textile fabrics, measuring the ease of passage of air through them * "Impermeable" (song), a song by Ha*Ash * Permeable Press, an American publishing company {{disambiguation