Act of bending back

Wiktionary Word definitions in Wiktionary
n. retorsion

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Retortion \Re*tor"tion\, n. [Cf. F. r['e]torsion. See Retort , v. t.] Act of retorting or throwing back; reflection or turning back. [Written also retorsion .] It was, however, necessary to possess some single term expressive of this intellectual retortion. ...

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1590s, from Medieval Latin retortionem (nominative retortio ), noun of action from past participle stem of Latin retorquere (see retort (v.)).