Brief reference, with no explanation, to a person, a text, a myth or a fact known outside the work, which brings with it the meaning of that other story.
In Hamlet
For Hecuba! / What's Hecuba to him, or he to Hecuba, / That he should weep for her? What would he do / Had he the motive and the cue for passion / That I have?
“Hecuba,” the queen who weeps at the fall of Troy, comes from another story, and the actors have just evoked her. Hamlet takes her as a measure: the actor weeps for someone who is nothing to him, and the prince, with a murdered father, stays still.
Act II: Feigned madness and the theater trap, Hamlet, alone
Well, God 'ild you! They say the owl was a baker's daughter. Lord, we know what we are, but know not what we may be.
Act IV: Exile, madness, and the trap, Ophelia, mad, to Claudius
There's a special providence in the fall of a sparrow. [...] The readiness is all.
Act V: Graveyard and duel, Hamlet, to Horatio
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