Definition of lenition in English:

lenition

noun

mass noun
  • (in Celtic languages) the process or result of palatalizing a consonant.

    • ‘The grammar involved in medieval Gaelic names often includes lenition, a "softening" of the initial consonant sound of words or names required by Gaelic grammar in certain situations.’

Origin

Early 20th century: from Latin lenis ‘soft’ + -ition, suggested by German Lenierung.

Pronunciation

lenition

/lɪˈnɪʃ(ə)n/