migration

  1. The (usually intramolecular) transfer of an atom or group during the course of a molecular rearrangement.
  2. The movement of a bond to a new position, within the same molecular entity is known as 'bond migration'. Allylic rearrangements, e.g.
    M03920
    exemplify both types of migration.
Source:
PAC, 1994, 66, 1077 (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1141