Sens communProperty of a porous solid to let water through.
according to the French Dictionary of Surface Hydrology
Sens techniqueProperty of a body, a solid - especially a soil, a rock - to be penetrated and crossed by a fluid, water in particular, under the effect of a potential gradient. A parameter expressing quantitatively this property, with respect to the characteristics of the fluid, water in particular: flow that can pass through a unit section of the solid considered, under the effect of a hydraulic load gradient unit, under determined conditions of pressure and temperature (homogeneous size at a speed, noted K).
According to the hydrologie.org website and Jean Margat, January 1999
Relu par le comité de relecture.