Which term best describes a solid area that does not allow water to pass through, often found above or below an aquifer?

The term that best describes a solid area that does not allow water to pass through is "aquiclude." An aquiclude is a layer of material, such as clay or dense rock, that can trap water within an aquifer and prevents water from moving freely. It serves as a barrier, often found above or below an aquifer, and is crucial for maintaining the water pressure in the aquifer.

An aquifer is a water-bearing rock layer that can transmit water and is designed to store and supply water. An aquitard is similar to an aquiclude but may allow some water to pass through, albeit at a significantly lower rate compared to an aquifer. An aqueduct, on the other hand, is a structure built to convey water across distances, typically used in human-made water systems. Thus, the best term for solid material that prevents water movement is aquiclude.