me|tath|e|sis

me|tath|e|sis «muh TATH uh sihs», noun, plural -ses «-seez».

1. the transposition of sounds, syllables, or letters in a word, as in English bird, Old English bridd: »

By inversion of sounds, called “metathesis”, many speakers change apron to apern (Scientific American).

2. the interchange of radicals between two compounds in a chemical reaction.

3. a change or reversal of condition. SYNONYM(S): transposition.

╂[earlier, (grammatical) interchange < Late Latin metaesis < Greek metáthesis transposition < metatithénai to transpose < meta- changed, over + tithénai to set]