1The action or process of mutating.
2The changing of the structure of a gene, resulting in a variant form that may be transmitted to subsequent generations, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes.
2.1count noun A distinct form resulting from genetic mutation.
Regular change of a sound when it occurs adjacent to another.
3.1 (in Celtic languages) change of an initial consonant in a word caused (historically) by the preceding word.
3.2 (in Germanic languages) the process by which the quality of a vowel was altered in certain phonetic contexts; umlaut.
Late Middle English: from Latin mutatio(n-), from mutare ‘to change’.