Related Words

Permeable: Allows another material to pass through without effecting the existing material.

Semipermeable Membrane: A membrane that allows some but not all of the components in a mixture to pass through it. Semipermeable membranes are used in dialysis.

Impermeable Layer: A layer of rock, sediment or soil that does not allow water to pass through. This could be caused by a lack of pore space or pore spaces that are so small that water molecules have difficult . . . View Full Definition

Selectively Permeable: Term describing a barrier that allows some chemicals to pass but not others. The cell membrane is such a barrier.

Oil Field: An underground accumulation of oil and gas concentrated beneath an impermeable trap, preventing its escape upward.

Aquifer (Unconfined): An aquifer that is not overlain by an impermeable rock unit. The water in this aquifer is under atmospheric pressure and is recharged by precipitation that falls on the land surface directly . . . View Full Definition

Base Flow: Water that seeps into a stream through a permeable rock or sediment unit that outcrops in the bottom or banks of the stream.

Reservoir: (or Natural Reservoir)The long-term host of the pathogen of an infectious disease. The long term host may not get the disease carried by the pathogen or it may be asymptomatic and non-lethal . . . View Full Definition

Trap: A defense designed to slow down the opposition's offense by trapping the puck in the neutral zone, then regaining control of it.

Aquifer (Confined): An aquifer that is bounded above and below by impermeable rock or sediment layers. There may or may not be enough pressure in the aquifer to make it an 'artesian aquifer'.