Definition of autoionization in US English:

autoionization

(also autoionisation)

noun

  • 1Chemistry. The spontaneous ionization of a substance or molecule; a reaction between two identical neutral molecules, especially in a solution, to produce an anion and a cation.

  • 2Physics. The spontaneous transition of an atom to an ionized state of lower energy with the emission of an electron (but no emission of radiation).

Origin

Early 20th century; earliest use found in Journal of the American Chemical Society. From auto- + ionization.

Pronunciation

autoionization

/ˌɔːtəʊˌʌɪənʌɪˈzeɪʃn/