Depression and elevation are downward and upward movements of the scapula or mandible.
The upward movement of the scapula and shoulder is elevation, while a downward movement is depression. These movements are used to shrug your shoulders.
Similarly, elevation of the mandible is the upward movement of the lower jaw used to close the mouth or bite on something, and depression is the downward movement that produces opening of the mouth (Picture 1 k).