A jump cut is a transition between two shots which appears to "jump" due to the way the shots are framed in relation to each other. Jump cuts are usually caused by framing which is quite similar, such as these two:
Over The Shoulder Shot:
This shot is framed from behind a person who is looking at the subject. The person facing the subject should usually occupy about 1/3 of the frame. This shot helps to establish the position of each person, and get the feel of looking at one person from the other's point of view. It's common to cut between these shots during a conversation, alternating the view between the different speakers.
Cut Away:
A cutaway is a shot that's usually of something other than the current action. It could be a different subject (eg. this cat when the main subject is its owner), a close up of a different part of the subject (eg. the subject's hands), or just about anything else.
Point Of View Shot:
This shot shows a view from the subject's perspective. It is usually edited in such a way that it is obvious whose POV it is (see the example below).