(Gk. meta 'over' + tithenai 'place'; µ¦ìÅÜ´«): Interchanging of letters, sounds or syllables within a word, e.g. Old English brid became Modern English bird through metathesis; a modern example would be pretty, purty.
Metathesis is a sound change that alters the order of phonemes in a word. The most common instance of metathesis is the reversal of the order of two adjacent phonemes. Many languages have words that show this phenomenon, and some use it as a regular part of their grammar (e.g.
The act, process, or result of exchange, substitution, or replacement of atoms and radicals; thus, by metathesis an acid gives up all or part of its hydrogen, takes on an equivalent amount of a metal or base, and forms a salt.