“The minimal definition of plot is ‘pattern.’ Only slightly less simple is ‘pattern of events.’ Plot is an intellectual formulation about the relations among the incidents and is, therefore, a guiding principle for the author and an ordering control for the reader.
“Because the plot consists of characters performing actions in incidents that comprise a ‘single, whole, and complete’ action, this relation involves conflict between opposing forces…Without conflict, plot hardly exists…These forces may be physical (or external), or they may be spiritual (or internal); but they must in any case afford an opposition. The struggle between the forces, moreover, comes to a head in one incident—the crisis—that forms the turning point and usually marks the moment of greatest suspense” (Source: Harmon & Holman, 394).
The term plot-driven is sometimes used to describe a work in which plot (or action) seems more important than characterization.
A short story, because of its restricted length, usually contains only one conflict, story line, or plot. However, novels usually contain one or more subplots in addition to the major plot. Subplots are mini-stories within the main story. They usually complement the main plot line in some way, either by reinforcing or contrasting with it. For example, if the main plot involves the way the protagonist reacts to a particular threat, subplots might demonstrate the way other characters deal with similar situations. Their reactions to and methods of coping with the situation may be similar to the protagonist's or may demonstrate other possibilities that the protagonist is unaware of or considers but rejects.
Also see: conflict.