A fracture in rock along which movement occurs is called a fault.

Here's a breakdown:

* Fracture: A break or crack in a rock.

* Fault: A fracture where there has been significant movement of the rock on either side of the fracture. This movement can be horizontal, vertical, or a combination of both.

Faults are responsible for many geological features, including:

* Earthquakes: When rocks on either side of a fault move suddenly, it releases energy as seismic waves, causing earthquakes.

* Mountains: The uplift of mountains often occurs along fault lines.

* Valleys: The sinking of land along fault lines can create valleys.

Let me know if you have any other questions!