Intrinsic permeability
"A measure of the relative ease with which a porous medium can transmit a fluid under a potential gradient and is a property of the medium alone" (Lohman et al 1972).
Sources
Drescher, W.J.,Jr., Ferris, J.G., Johnson, A.I., McGuinness, C.L., Piper, A.M., Rorabaugh, M.I., Stallman, R.W., and Theis, C.V., 1972, Definitions of selected ground-water terms—Revisions and conceptual refinements: U.S. Geological Survey Water-Supply Paper 1988.