mutation

Short definition from Wiktionary

Noun

1. 1
   Any alteration or change.
2. 2
   Any heritable change of the base-pair sequence of genetic material.
3. 3
   A mutant.
4. 4
   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.
5. 5
   The transfer of title of an asset in a register.
6. 6
   A group of thrushes.