Shot/reverse shot is a very important rule and technique that has to be followed and used when editing. It uses both the 180 degree rule and the eye level rule. Shot reverse shot is defined as this:
“A film technique wherein one character is shown looking (often off-screen) at another character, and then the other character is shown looking “back” at the first character. Since the characters are shown facing in opposite directions, the viewer unconsciously assumes that they are looking at each other.”
-Bordwell, David; Thompson, Kristin (2006). Film Art: An Introduction. New York: McGraw-Hill.
Above is an example of Shot/Reverse Shot.
Shot/Reverse Shot is used in the majority of films. It helps the viewer understand the scenes and where the movie is going, by using dialogue and keeping the dialogue continuous.
Below is a scene that perfectly shows the technique of Shot/Reverse Shot from the film Light Sleeper:
Another great example of Shot/Reverse shot is in Rocky:
In the Shining, Stanley Kubrick uses a Shot/Reverse Shot in the interview scene as seen below”