What process involves material moving as a rigid mass down a slope?

The process where material moves as a rigid mass down a slope is known as sliding, which is characteristic of the transition of loose material or rock along a defined surface. In a slide, the mass maintains its structural integrity as it shifts, typically occurring on steeper terrains where the gravitational force exceeds the slope's resistance.

Slides can be distinguished from other mass wasting processes like flow, which involves a more fluid movement of material and is often saturated with water, allowing it to behave like a liquid. Glide refers specifically to a smooth movement along a plane, while falls describe the process where materials drop freely from steep faces, usually due to gravity. The key distinction of sliding is the mass retaining its form while moving down a slope, which aligns with the definition provided.