A rhetorical device where two clauses mirror each other in reversed order, like a grammatical reflection.
Chiasmus is a rhetorical pattern where two or more clauses are structured so that the second reverses the order of the first. The name comes from the Greek letter chi (X), and you can think of it as a sentence that crosses over itself. "Ask not what your country can do for you - ask what you can do for your country" is the textbook example: country/you flips to you/country, and the reversal transforms the meaning.
Chiasmus makes sentences feel balanced, memorable, and almost mathematically elegant. It forces the reader to see a relationship between two ideas by literally inverting them. In fiction, it can crystallize a theme, mark a character's transformation, or deliver a line of dialogue that sticks in the reader's mind long after the book is closed.
"Ask not what your country can do for you - ask what you can do for your country." The reversal turns a passive expectation into an active challenge.
"Fair is foul, and foul is fair" - the witches' chiasmus announces the play's central theme: nothing is what it seems, and every value will be inverted.
Fitzgerald uses chiastic structures throughout, reflecting the novel's obsession with mirrors, reflections, and the gap between perception and reality.
Chiasmus only works when the reversal reveals something - a contrast, an irony, a deeper truth. If the inversion doesn't add meaning, it just sounds like you're being clever for its own sake.
Antithesis presents opposing ideas ("it was the best of times, it was the worst of times"). Chiasmus specifically reverses the structure (A-B becomes B-A). They overlap but aren't the same thing.
One well-placed chiasmus per story or chapter is plenty. It's a spotlight - if you turn it on everywhere, nothing stands out.
Write five chiastic sentences about your protagonist's journey. Start with the formula: "She used to [A] [B], but now she [B] [A]." For example: "She used to run from silence, but now silence runs from her." Once you've got five, pick the one that best captures your character's arc and use it in your story.