180 degree rule

A rule stating that a camera should be placed somewhere inside 180 degrees on a particular side of the invisible line of a shot containing two people filmed in sequence. If the camera crosses the line, confusion results for the film viewers, because it makes it look like the people are switching places as one watches the film. The two characters in the scene should always have the same left/right relationship.

Shot reverse shot


Shot reverse shot  is a film technique where one character is shown looking at another character (often off-screen), and then the other character is shown looking back at the first character. Since the characters are shown facing in opposite directions, the viewer assumes that they are looking at each other.  
Shot reverse shot has to be used in films because if it is not used there will always be a camera in the background, which obviously is not acceptable.

A match cut

^{A match cut, also called a graphic match, is a cut in film editing between either two different objects, two different spaces, or two different compositions in which an object in the two shots graphically match, often helping to establish a strong continuity of action and linking the two shots metaphorically.}