The word ‘chiasm’ or ‘chiasmus’ comes from the Greek letter chi, written χ, and it denotes exactly that crossed intertwining shape. In biology, it refers to the crossing of two nerves or ligaments. In language, it is the rhetorical device in which one phrase is countered by another inverting the same words, as when John F. Kennedy said, ‘Ask not what your country can do for you, but what you can do for your country,’ or when Mae West said, ‘It’s not the men in my life, it’s the life in my men.’
