chiasmus
noun [uncountable, countable] (specialist)a technique used in writing or in speeches, in which words, ideas, etc. are repeated in the opposite order 回环，交错配列（对词、思想等的倒序重复排列） Word Originmid 17th cent. (in the sense ‘crosswise arrangement’): modern Latin, from Greek khiasmos, from khiazein ‘mark with the letter chi’, from khi ‘chi’, the twenty-second letter of the Greek alphabet.