1. n. [Geology]

A discrete void within a rock, which can contain air, water, hydrocarbons or other fluids. In a body of rock, the percentage of pore space is the porosity.

See: connate water,  dirty,  effective porosity,  formation pressure,  formation water,  fracture,  fracture porosity,  groundwater,  interstitial water,  moldic porosity,  normal pressure,  permeability,  porosity,  saturation,  stylolite,  vug,  weathered layer