noun

• (genetics) Any heritable change of the base-pair sequence of genetic material.
  "Plant breeding is always a numbers game.[…]The wild species we use are rich in genetic variation, […]. In addition, we are looking for rare alleles, so the more plants we try, the better. These rarities may be new mutations, or they can be existing ones that are neutral—or are even selected against—in a wild population. A good example is mutations that disrupt seed dispersal, leaving the seeds on the heads long after they are ripe."
• (linguistics) An alteration in a particular sound of a word, especially the initial consonant, which is triggered by the word's morphological or syntactic context and not by its phonological context.
• (law) The transfer of title of an asset in a register.
• (rare, collective noun) A group of thrushes.
  "Birdwatchers would enjoy a host of sparrows, a herd of swans, a descent of woodpeckers, a herd of wrens, and mutation of thrushes."