Final answer:
Permeability is the property affecting the ability of rock or sediment to transmit groundwater, based on the interconnectedness of its pores.
Step-by-step explanation:
Permeability is defined as the interconnectedness of pores in a rock or sediment and controls the ease of groundwater transmission through a material. This is a crucial aspect of hydrogeology, which is the area of geology that deals with the distribution and movement of groundwater in the Earth's crust. Permeability not only depends on the existence of pores within the rock but also requires these pores to be interconnected; if they are not connected, water cannot flow through the rock. Materials such as sandstone and limestone have high permeability and form excellent aquifers, which are geologic units that can yield significant amounts of groundwater. In contrast, impermeable rocks, like shale or un-fractured igneous and metamorphic rocks, act as confining layers and prevent the flow of water.