An inverted parallelism; the reversal of the order of corresponding words or phrases (with or without exact repetition) in successive clauses which are usually parallel in syntax, as Pope's "a fop their passion, but their prize a sot," or Goldsmith's "to stop too fearful, and too faint to go."
Sidelight: While the term, chiasmus, is usually used in reference to syntax and word order, it also includes the repetition in reverse of any element of a poem, including sound patterns.
Sidelight: An antimetabole (an-tye-muh-TAB-uh-lee) is a type of chiasmus in which the words reversed involve a repetition of the same words, as "do not live to eat, but eat to live," or Shakespeare's "Remember March, the ides of March remember." The distinction is not generally observed, however.
(See also Anastrophe, Hypallage)
(Compare Envelope, Palindrome)

This definition is in context to Poetry. See more contextual defintions for Chiasmus (Kye-az-mus).