Definition
A reference within a literary text to some person, place, or event outside the text. Allusions that refer to events more or less contemporary with the text are called topical allusions. Those referring to specific people are personal allusions. An example of a topical allusion is the reference of the drunken porter in Macbeth to "an equivocator . . . who committed treason enough for God's sake . . ." This is a reference to Father Henry Garnet, a Jesuit priest who justified equivocation (a form of lying) during his trial for treason in connection with the Gunpowder Plot of 1605. An example of personal allusion is William Butler Yeats's reference to "golden thighed Pythagoras" in his poem "Among School Children."
Other uses of an allusion might be to summarize an important idea (as in the concluding line from King Kong: "It was Beauty killed the Beast"), or to point to an ironic contrast between contemporary life and a heroic past (as in James Joyce's classical parallels in Ulysses [1922], in which the heroic deeds in the Odyssey are implicitly contrasted to the banal details of everyday life in modern Dublin).In film, homage is the term for one director's allusion to another's work.