Grass Valley NewsEdit LT v.4.1 - Manual (Page 144)

Chapter 9 Adding Transitions to Your Sequences
144 Digital News Production
Pushes
A push moves the second image in the direction chosen onto the screen, looking
like the first image is “pushed” out of the way.
Slides
A slide moves either the old image or the new image. The old image moves to
reveal the new image or the new image moves to conceal the old image.
A black arrow indicates the direction and path the second image takes moving
into the frame. A white arrow indicates a reverse slide, where the first image
slides to reveal the second image.