Meaning of lenition

le•ni•tion

Pronunciation: (li-nish'un), [key]
— n.
  1. a phonological process that weakens consonant articulation at the ends of syllables or between vowels, causing the consonant to become voiced, spirantized, or deleted.
  2. a type of Celtic mutation that derives historically from phonological lenition.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.