metathesis (n.)

1570s, "transposition of letters in a word;" c. 1600, "rhetorical transposition of words," from Late Latin metathesis, from Greek metathesis "change of position, transposition, change of opinion," from stem of metatithenai "to transpose," from meta "change" (see meta-) + tithenai "to place, to set," from reduplicated form of PIE root *dhe- "to set, put." Plural is metatheses. Related: Metathetic.