Progression - a continuous and connected change over time.

Applied Concept: Progression implies or illustrates a continuous transition. It can include (but is not limited to) a change of position from one position to another, a change in orientation, a change in direction, or a change in color. A car driving smoothly from one location to another is a progression; a car that must stop at many stop-lights along the way is not a progression (though it could be many small progressions).

In the image below, the first row of shapes does not exhibit a progression - the transition is not continuous. The second row of shapes exhibits a progression since the circle transforms into a square through a continuous transition.

Progression can refer to motion:

The red circle has a progression of size and position.
The yellow circle has a progression of size, but it does not have a progression of position - the change in position is not continuous.