metathesis

/məˈtæθəsɪs/
noun
  1. The process in which two sounds or letters in a word change places, often over time or in different dialects.
    • The word 'ask' was once 'aks' in Old English, an example of metathesis.
    • Metathesis explains why 'bird' was once 'brid' in earlier English.
    • Some people say 'nucular' instead of 'nuclear' because of metathesis.
  2. A chemical reaction in which two compounds exchange parts to form two new compounds.
    • Olefin metathesis is an important reaction in creating new carbon-carbon bonds.
    • The chemist explained how metathesis can produce useful polymers.
    • In the lab, we used a metathesis reaction to swap the ions between two salts.