Spectacle is an element of staged drama that evokes an emotional response from the audience.
The famous Greek philosopher Aristotle considered plays to be among the highest art forms. Aristotle wrote that good plays are "an imitation of an action that is serious, complete and of a certain magnitude," and consisted of six characteristics. In his 335 B.C. work, "Poetics," Aristotle defines the six characteristics as Plot, Characters, Thought, Diction, Spectacle and Melody.
Plot
The plot is an arrangement of events that forms the structure of the play. The play's structure must include a beginning, middle and an ending. Events should unfold logically and the playwright should avoid coincidence and resolutions that depend on intervention from forces outside the interior reality of the play.
Characters
According to Aristotle, characters in a play should be true to their nature, social class and role. Characters should have flaws, but have an air of dignity. The characters' function is to support the plot through the choices made which spawn a chain of events that move the story to its conclusion.
Thought
Thought refers to moments in a play where a character's true nature is revealed and the themes of the play are articulated. King Richard's "This is the winter of our discontent" monologue from "Richard III" or the "coffee is for closers" bit from "Glengarry Glen Ross" are excellent examples of this principle.
Diction
Diction refers to the playwright's elevated use of language and command of metaphor. William Shakespeare is famous for his command of metaphor and clever word play.
Melody
Melody refers to the chorus. Classical plays in ancient Greece and Rome included a choral element --- a group that spoke or sang in unison during interludes in the play. The role of the chorus was to serve as another character in the play, to comment on the action and contribute to the unity of the plot.
Spectacle
Although Aristotle considered spectacle to be the least important element in a play, he understood that a spectacular or dramatic effect could engage the audience on an emotional level. An example of spectacle would be Jocasta's suicide or Oedipus blinding himself in Sophocles' "Oedipus Rex."