Wide Shot (WS)
In the wide shot, the subject takes up the full frame. In this case, the boy's feet are almost at the bottom of frame and his head is almost at the top. Obviously the subject doesn't take up the whole width and height of the frame, since this is as close as we can get without losing any part of him. The small amount of room above and below the subject can be thought of as safety room — you don't want to be cutting the top of the head off. It would also look uncomfortable if his feet and head were exactly at the top and bottom of frame.
As with many shot types, the wide shot means different things to different people. However the wide shot seems to suffer more from varying interpretations than other types. Many people take the WS to mean something much wider than our example, i.e. what we would call a very wide shot.