Pan&Scan is a techinique for adapting a 16:9 or 2.35:1 film into a 4:3 ratio (a fullscreen TV). It crops the image in the middle, sometimes moving the selected part of the screen to the left or to the right. Sometimes this create a noticeable jerky camera movement to the right or to the left, when a character moves from one part of the screen to another, for example. So far the best example on how horrible pan&scan really is is the fullscreen version of "close encounters", the pan&scan movement happens on almost every scene, and it's so annoying the movie gets almost unwatchable.