CHIASMUS
chiasmus
(noun) inversion in the second of two parallel phrases
Source: WordNet® 3.1
Etymology
Noun
chiasmus (countable and uncountable, plural chiasmi or chiasmuses)
(rhetoric) An inversion of the relationship between the elements of phrases.
Source: Wiktionary
Chi*as"mus, n. Etym: [NL., fr. Gr. Chiasm.] (Rhet.)
Definition: An inversion of the order of words or phrases, when repeated or
subsequently referred to in a sentence; thus,
If e'er to bless thy sons My voice or hands deny, These hands let
useful skill forsake, This voice in silence die. Dwight.
Source: Webster’s Unabridged Dictionary 1913 Edition