Here's a breakdown:

* Fault: A fracture in the Earth's crust where rocks have moved past each other.

* Hanging Wall: The block of rock that lies above the fault plane.

* Footwall: The block of rock that lies below the fault plane.

Think of it like this: Imagine a mine shaft. The hanging wall is the rock that you would be "hanging" onto, and the footwall is the rock you're standing on.

The movement of the hanging wall relative to the footwall determines the type of fault:

* Normal Fault: The hanging wall moves down relative to the footwall.

* Reverse Fault: The hanging wall moves up relative to the footwall.

* Strike-Slip Fault: The blocks move horizontally past each other.