pervious

Pervious is an English adjective describing a material or surface that allows liquids or gases to pass through it. In geology, hydrology, and civil engineering, pervious materials are permeable and have interconnected voids or pores that permit infiltration and drainage. Common examples include pervious concrete and other porous pavements, certain soils, and some geosynthetic membranes.

The term contrasts with impervious (or non-porous) materials that resist infiltration. The effectiveness of pervious materials depends on porosity, pore connectivity, and maintenance; clogging by sediment, silt, or biological growth can reduce permeability and drainage performance.

Figuratively, "pervious to" describes something or someone susceptible to influence, persuasion, or criticism, as in "pervious to persuasion." The usual opposite is "impervious to."

Etymology: from Latin pervius meaning passable or through-going, via Old French pervi, entering English in the late Middle Ages. It is often confused with "previous," which has a different meaning and origin.

See also: impermeable; permeable; porous; porosity; hydrology.