From IRC Improv Wiki
In the nomenclature of comedy, “beat” has a number of meanings:
- Major dramatic sections of a scene are called beats. A beat is a significant event that leads to changed circumstances. It has a beginning, middle and end of its own. Although an entire scene could be comprised in one beat, a single scene usually contains more. In scripted theater, a list of a scene’s beats is called a beat sheet.
- A beat is a moment’s pause. Pausing purposefully onstage is called “taking a beat.” “A couple of beats” is, of course, a longer pause.
- In a longform, a beat is any time a specific scene or situation is visited. For example, in a traditional Harold, the first three scenes of the form are also called First Beats; it's the first time we are visiting that scene. When we revisit those three scenes later in the form we are creating those scenes' Second or Third Beats. When we revisit them, we also heighten them, by either more deeply exploring the characters and relationships, playing the Game, exploring an Analogous Scene, or any of a number of other methods.