A beat is the smallest element of story structure. Bigger: scene.

Alternative names: “motivation-reaction unit” and “clip.”

McKee defines a beat as follows:¹¹1 Robert McKee, Story: Substance, Structure, Style and the Principles of Screenwriting (Methuen, 2014). 

Inside the scene is the smallest element of structure, the Beat. (Not to be confused with [beat], an indication within a column of dialogue meaning “short pause”.)

A BEAT is an exchange of behavior in action/reaction. Beat by beat these changing behaviors shape the turning of a scene.

Ingermanson uses the term clip instead of beat, but they mean the same as far as I can tell:²²2 Randall Ingermanson and Peter Economy, Writing Fiction For Dummies (Hoboken, N.J.: Wiley Publishing, Inc., 2010). 

That paragraph or group of paragraphs forms a unit in fiction — the lowest layer of plot complexity. We need a technical term for this unit of fiction. Since there doesn’t seem to be such a technical term, we’re going to create one. We’ll use the analogy of a film clip, which is a sequence of video frames.

We define a clip to be a sequence of sentences focused on a single character that contains any mix of action, dialogue, interior emotion, interior monologue, and description.

See also:

• Writing beats