Here's why:

* Aquicludes: This term emphasizes the layer's ability to prevent the flow of water. They act as barriers, stopping groundwater from moving through them.

* Confining layers: This term highlights their role in trapping groundwater. They act as a "cap" above an aquifer, holding the water in place.

Important Note: While aquicludes are generally impermeable, they might have some limited permeability under very high pressures.

Let me know if you'd like to learn more about aquifers, aquitards, or other aspects of groundwater!