METATHESIS

[me.tath.e.sis] n, pl -e.ses [LL, fr. Gk, fr. metatithenai to transpose, fr. meta- + tithenai to place--more at do] (1577): a change of place or condition: as a: transposition of two phonemes in a word b: a chemical reaction in which different kinds of molecules exchange parts to form other kinds of molecules -- met.a.thet.i.cal or met.a.thet.ic adj -- met.a.thet.i.cal.ly adv